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arxiv_dataset-98001805.06955 | Coupling Levy measures and comparison principles for viscosity solutions
math.AP
We prove new comparison principles for viscosity solutions of non-linear
integro-differential equations. The operators to which the method applies
include but are not limited to those of L\'evy-It\^o type. The main idea is to
use an optimal transport map to couple two different L\'evy measures, and use
the resulting coupling in a doubling of variables argument
| arxiv topic:math.AP |
arxiv_dataset-98011805.07055 | Surjectivity in Fr\'echet spaces
math.FA
We prove surjectivity result in Fr\'echet spaces of Nash-Moser type. That is,
with uniform estimates over all semimorms.
Our method works for functions which are only continuous and G\^ateaux
differentiable like in the recent result of Ekeland.
We present the results in multi-valued setting exploring the relevant notions
of map regularity.
| arxiv topic:math.FA |
arxiv_dataset-98021805.07155 | Partial Cartesian Graph Product
cs.PL math.CO
In this paper we define a new product-like binary operation on directed
graphs, and we discuss some of its properties. We also briefly discuss its
application in constructing the subtyping relation in generic nominally-typed
object-oriented programming languages.
| arxiv topic:cs.PL math.CO |
arxiv_dataset-98031805.07255 | A convergent finite difference scheme for the Ostrovsky--Hunter equation
with Dirichlet boundary conditions
math.AP
We prove convergence of a finite difference scheme to the unique entropy
solution of a general form of the Ostrovsky--Hunter equation on a bounded
domain with non-homogeneous Dirichlet boundary conditions. Our scheme is an
extension of monotone schemes for conservation laws to the equation at hand.
The convergence result at the center of this article also proves existence of
entropy solutions for the initial-boundary value prob lem for the general
Ostrovsky--Hunter equation. Additionally, we show uniqueness using
Kru\v{z}kov's doubling of variables technique. We also include numerical
examples to confirm the convergence results and determine rates of convergence
experimentally.
| arxiv topic:math.AP |
arxiv_dataset-98041805.07355 | The Sub-Geometric Phases in Density Matrix
quant-ph
In this letter, the generalization of geometric phase in density matrix is
presented, we show that the extended sub-geometric phase have unified
expression whatever in adiabatic or nonadiabatic procedure, the relations
between them and the usual Berry phase or Aharonov-Anandan phase are
established. We also demonstrated the influence of sub-geometric phases on the
physical observables. Finally, our treatment is naturally used to investigate
the geometric phase in mixed state.
| arxiv topic:quant-ph |
arxiv_dataset-98051805.07455 | Subspace Selection via DR-Submodular Maximization on Lattices
cs.DS
The subspace selection problem seeks a subspace that maximizes an objective
function under some constraint. This problem includes several important machine
learning problems such as the principal component analysis and sparse
dictionary selection problem. Often, these problems can be solved by greedy
algorithms. Here, we are interested in why these problems can be solved by
greedy algorithms, and what classes of objective functions and constraints
admit this property. To answer this question, we formulate the problems as
optimization problems on lattices. Then, we introduce a new class of functions,
directional DR-submodular functions, to characterize the approximability of
problems. We see that the principal component analysis, sparse dictionary
selection problem, and these generalizations have directional
DR-submodularities. We show that, under several constraints, the directional
DR-submodular function maximization problem can be solved efficiently with
provable approximation factors.
| arxiv topic:cs.DS |
arxiv_dataset-98061805.07555 | Second-order photonic topological insulator with corner states
cond-mat.mtrl-sci
Higher-order topological insulators (HOTIs) which go beyond the description
of conventional bulk-boundary correspondence, broaden the understanding of
topological insulating phases. Being mainly focused on electronic materials,
HOTIs have not been found in photonic systems yet. In this article, we propose
a type of two-dimensional second-order photonic crystals with zero-dimensional
corner states and one-dimensional boundary states for optical frequencies. All
of these states are topologically non-trivial and can be understood based on
the theory of topological polarization. Moreover, by tuning the
easily-fabricated structure of the photonic crystals, we can realize different
topological phases with unique topological boundary states straightforwardly.
Our result can be generalized to higher dimensions and provides unprecedented
venues for higher-order photonic topological insulators and semimetals.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-98071805.07655 | Coboundaries of nonconventional ergodic averages
math.DS
Let $(X,\mathcal{A}, \mu)$ be a probability measure space and let $T_i,$
$1\leq i\leq H,$ be invertible bi measurable measure preserving transformations
on this measure space. We give a sufficient condition for the product of $H$
bounded functions $f_1, f_2, ..., f_H$ to be a coboundary. This condition turns
out to be also necessary when one seeks bounded coboundaries.
| arxiv topic:math.DS |
arxiv_dataset-98081805.07755 | Dunkl jump processes: relaxation and a phase transition
math-ph math.MP math.PR
Dunkl processes are multidimensional Markov processes defined through the use
of Dunkl operators. These processes have discontinuities, and they can be
separated into their continuous (radial) part, and their discontinuous (jump)
part. While radial Dunkl processes have been studied thoroughly due to their
relationship to families of stochastic particle systems such as the Dyson model
and Wishart-Laguerre processes, Dunkl jump processes have gone largely
unnoticed after the initial work of Gallardo, Yor and Chybiryakov. We study the
dynamical properties of these processes, and we derive their master equation.
By calculating the asymptotic behavior of their total jump rate, we find that
the jump processes of types $A_{N-1}$ and $B_N$ undergo a phase transition when
the parameter $\beta$ decreases toward one in the bulk scaling limit. In
addition, we show that the relaxation behavior of these processes is given by a
non-trivial power law, and formulate a conjecture for the jump rate asymptotics
based on numerical simulations.
| arxiv topic:math-ph math.MP math.PR |
arxiv_dataset-98091805.07855 | Squares of Tribonacci numbers
math.CO
We prove some identities for the squares of generalized Tribonacci numbers.
Various summation identities involving these numbers are derived.
| arxiv topic:math.CO |
arxiv_dataset-98101805.07955 | Regularity for fully nonlinear integro-differential operators with
kernels of variable orders
math.AP
We consider fully nonlinear elliptic integro-differential operators with
kernels of variable orders, which generalize the integro-differential operators
of the fractional Laplacian type in \cite{CS}. Since the order of
differentiability of the kernel is not characterized by a single number, we use
the constant \begin{align*} C_\varphi = \left( \int_{\mathbb{R}^n} \frac{1-\cos
y_1}{\vert y \vert^n \varphi (\vert y \vert)} \, dy \right)^{-1} \end{align*}
instead of $2-\sigma$, where $\varphi$ satisfies a weak scaling condition. We
obtain the uniform Harnack inequality and H\"older estimates of viscosity
solutions to the nonlinear integro-differential equations.
| arxiv topic:math.AP |
arxiv_dataset-98111805.08055 | Higher spin supercurrents in anti-de Sitter space
hep-th math-ph math.MP
We propose higher spin supercurrent multiplets for ${\cal N}=1$
supersymmetric field theories in four-dimensional anti-de Sitter space (AdS).
Their explicit realisations are derived for various supersymmetric theories,
including a model of $N$ massive chiral scalar superfields with an arbitrary
mass matrix. We also present new off-shell gauge formulations for the massless
${\cal N}=1$ supersymmetric multiplet of integer superspin $s$ in AdS, where $s
=2,3,\dots$, as well as for the massless gravitino multiplet (superspin $s=1$)
which requires special consideration.
| arxiv topic:hep-th math-ph math.MP |
arxiv_dataset-98121805.08155 | Physical descriptor for the Gibbs energy of inorganic crystalline solids
and temperature-dependent materials chemistry
cond-mat.mtrl-sci
The Gibbs energy, G, determines the equilibrium conditions of chemical
reactions and materials stability. Despite this fundamental and ubiquitous
role, G has been tabulated for only a small fraction of known inorganic
compounds, impeding a comprehensive perspective on the effects of temperature
and composition on materials stability and synthesizability. Here, we use the
SISSO (sure independence screening and sparsifying operator) approach to
identify a simple and accurate descriptor to predict G for stoichiometric
inorganic compounds with ~50 meV/atom (~1 kcal/mol) resolution, and with
minimal computational cost, for temperatures ranging from 300-1800 K. We then
apply this descriptor to ~30,000 known materials curated from the Inorganic
Crystal Structure Database (ICSD). Using the resulting predicted thermochemical
data, we generate thousands of temperature-dependent phase diagrams to provide
insights into the effects of temperature and composition on materials
synthesizability and stability and to establish the temperature-dependent scale
of metastability for inorganic compounds.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-98131805.08255 | Algorithmic and algebraic aspects of unshuffling permutations
cs.DS math.CO
A permutation is said to be a square if it can be obtained by shuffling two
order-isomorphic patterns. The definition is intended to be the natural
counterpart to the ordinary shuffle of words and languages. In this paper, we
tackle the problem of recognizing square permutations from both the point of
view of algebra and algorithms. On the one hand, we present some algebraic and
combinatorial properties of the shuffle product of permutations. We follow an
unusual line consisting in defining the shuffle of permutations by means of an
unshuffling operator, known as a coproduct. This strategy allows to obtain easy
proofs for algebraic and combinatorial properties of our shuffle product. We
besides exhibit a bijection between square $(213,231)$-avoiding permutations
and square binary words. On the other hand, by using a pattern avoidance
criterion on directed perfect matchings, we prove that recognizing square
permutations is {\bf NP}-complete.
| arxiv topic:cs.DS math.CO |
arxiv_dataset-98141805.08355 | Opening the black box of deep learning
cs.LG stat.ML
The great success of deep learning shows that its technology contains
profound truth, and understanding its internal mechanism not only has important
implications for the development of its technology and effective application in
various fields, but also provides meaningful insights into the understanding of
human brain mechanism. At present, most of the theoretical research on deep
learning is based on mathematics. This dissertation proposes that the neural
network of deep learning is a physical system, examines deep learning from
three different perspectives: microscopic, macroscopic, and physical world
views, answers multiple theoretical puzzles in deep learning by using physics
principles. For example, from the perspective of quantum mechanics and
statistical physics, this dissertation presents the calculation methods for
convolution calculation, pooling, normalization, and Restricted Boltzmann
Machine, as well as the selection of cost functions, explains why deep learning
must be deep, what characteristics are learned in deep learning, why
Convolutional Neural Networks do not have to be trained layer by layer, and the
limitations of deep learning, etc., and proposes the theoretical direction and
basis for the further development of deep learning now and in the future. The
brilliance of physics flashes in deep learning, we try to establish the deep
learning technology based on the scientific theory of physics.
| arxiv topic:cs.LG stat.ML |
arxiv_dataset-98151805.08455 | Context-Aware Sequence-to-Sequence Models for Conversational Systems
cs.CL cs.AI
This work proposes a novel approach based on sequence-to-sequence (seq2seq)
models for context-aware conversational systems. Exist- ing seq2seq models have
been shown to be good for generating natural responses in a data-driven
conversational system. However, they still lack mechanisms to incorporate
previous conversation turns. We investigate RNN-based methods that efficiently
integrate previous turns as a context for generating responses. Overall, our
experimental results based on human judgment demonstrate the feasibility and
effectiveness of the proposed approach.
| arxiv topic:cs.CL cs.AI |
arxiv_dataset-98161805.08555 | MoMEMta, a modular toolkit for the Matrix Element Method at the LHC
hep-ph hep-ex
The Matrix Element Method has proven to be a powerful method to optimally
exploit the information available in detector data. Its widespread use is
nevertheless impeded by its complexity and the associated computing time.
MoMEMta, a C++ software package to compute the integrals at the core of the
method, provides a versatile implementation of the Matrix Element Method to
both the theory and experiment communities. Its modular structure covers the
needs of experimental analysis workflows at the LHC without compromising ease
of use on simpler and smaller simulated samples used for phenomenological
studies. With respect to existing tools, MoMEMta improves on usability and
flexibility. In this paper, we present version 1.0 of MoMEMta, together with
examples illustrating the wide range of applications at the LHC accessible for
the first time with a single tool.
| arxiv topic:hep-ph hep-ex |
arxiv_dataset-98171805.08655 | The first 62 AGN observed with SDSS-IV MaNGA - II: resolved stellar
populations
astro-ph.GA
We present spatially resolved stellar population age maps, average radial
profiles and gradients for the first 62 Active Galactic Nuclei (AGN) observed
with SDSS-IV MaNGA to study the effects of the active nuclei on the star
formation history of the host galaxies. These results, derived using the
STARLIGHT code, are compared with a control sample of non-active galaxies
matching the properties of the AGN hosts. We find that the fraction of young
stellar populations (SP) in high-luminosity AGN is higher in the inner ($R \leq
0.5\,R_e$) regions when compared with the control sample; low-luminosity AGN,
on the other hand, present very similar fractions of young stars to the control
sample hosts for the entire studied range ($1\,R_e$). The fraction of
intermediate age SP of the AGN hosts increases outwards, with a clear
enhancement when compared with the control sample. The inner region of the
galaxies (AGN and control galaxies) presents a dominant old SP, whose fraction
decreases outwards. We also compare our results (differences between AGN and
control galaxies) for the early and late-type hosts and find no significant
differences. In summary, our results suggest that the most luminous AGN seems
to have been triggered by a recent supply of gas that has also triggered recent
star formation ($t\,\leq\,40\,Myrs$) in the central region.
| arxiv topic:astro-ph.GA |
arxiv_dataset-98181805.08755 | Energy-aware tree network formation among computationally weak nodes
cs.NI cs.DC
We study the fundamental problem of distributed network formation among
mobile agents of limited computational power that aim to achieve energy balance
by wirelessly transmitting and receiving energy in a peer-to-peer manner.
Specifically, we design simple distributed protocols consisting of a small
number of states and interaction rules for the formation of arbitrary and k-ary
tree networks. Furthermore, we evaluate (theoretically and also using computer
simulations) a plethora of energy redistribution protocols that exploit
different levels of knowledge in order to achieve desired energy distributions
among the agents which require that every agent has exactly or at least twice
the energy of the agents of higher depth, according to the structure of the
network. Our study shows that without using any knowledge about the network
structure, such energy distributions cannot be achieved in a timely manner,
meaning that there might be high energy loss during the redistribution process.
On the other hand, only a few extra bits of information seem to be enough to
guarantee quick convergence to energy distributions that satisfy particular
properties, yielding low energy loss.
| arxiv topic:cs.NI cs.DC |
arxiv_dataset-98191805.08855 | Rate-Optimal Denoising with Deep Neural Networks
cs.IT cs.LG eess.SP math.IT math.OC
Deep neural networks provide state-of-the-art performance for image
denoising, where the goal is to recover a near noise-free image from a noisy
observation. The underlying principle is that neural networks trained on large
datasets have empirically been shown to be able to generate natural images well
from a low-dimensional latent representation of the image. Given such a
generator network, a noisy image can be denoised by i) finding the closest
image in the range of the generator or by ii) passing it through an
encoder-generator architecture (known as an autoencoder). However, there is
little theory to justify this success, let alone to predict the denoising
performance as a function of the network parameters. In this paper we consider
the problem of denoising an image from additive Gaussian noise using the two
generator based approaches. In both cases, we assume the image is well
described by a deep neural network with ReLU activations functions, mapping a
$k$-dimensional code to an $n$-dimensional image. In the case of the
autoencoder, we show that the feedforward network reduces noise energy by a
factor of $O(k/n)$. In the case of optimizing over the range of a generative
model, we state and analyze a simple gradient algorithm that minimizes a
non-convex loss function, and provably reduces noise energy by a factor of
$O(k/n)$. We also demonstrate in numerical experiments that this denoising
performance is, indeed, achieved by generative priors learned from data.
| arxiv topic:cs.IT cs.LG eess.SP math.IT math.OC |
arxiv_dataset-98201805.08955 | Coded Caching via Line Graphs of Bipartite Graphs
cs.IT math.IT
We present a coded caching framework using line graphs of bipartite graphs. A
clique cover of the line graph describes the uncached subfiles at users. A
clique cover of the complement of the square of the line graph gives a
transmission scheme that satisfies user demands. We then define a specific
class of such caching line graphs, for which the subpacketization, rate, and
uncached fraction of the coded caching problem can be captured via its graph
theoretic parameters. We present a construction of such caching line graphs
using projective geometry. The presented scheme has a rate bounded from above
by a constant with subpacketization level $q^{O((log_qK)^2)}$ and uncached
fraction $\Theta(\frac{1}{\sqrt{K}})$, where $K$ is the number of users and $q$
is a prime power. We also present a subpacketization-dependent lower bound on
the rate of coded caching schemes for a given broadcast setup.
| arxiv topic:cs.IT math.IT |
arxiv_dataset-98211805.09055 | Grounding the Semantics of Part-of-Day Nouns Worldwide using Twitter
cs.CL
The usage of part-of-day nouns, such as 'night', and their time-specific
greetings ('good night'), varies across languages and cultures. We show the
possibilities that Twitter offers for studying the semantics of these terms and
its variability between countries. We mine a worldwide sample of multilingual
tweets with temporal greetings, and study how their frequencies vary in
relation with local time. The results provide insights into the semantics of
these temporal expressions and the cultural and sociological factors
influencing their usage.
| arxiv topic:cs.CL |
arxiv_dataset-98221805.09155 | AdGraph: A Graph-Based Approach to Ad and Tracker Blocking
cs.CY cs.LG
User demand for blocking advertising and tracking online is large and
growing. Existing tools, both deployed and described in research, have proven
useful, but lack either the completeness or robustness needed for a general
solution. Existing detection approaches generally focus on only one aspect of
advertising or tracking (e.g. URL patterns, code structure), making existing
approaches susceptible to evasion.
In this work we present AdGraph, a novel graph-based machine learning
approach for detecting advertising and tracking resources on the web. AdGraph
differs from existing approaches by building a graph representation of the HTML
structure, network requests, and JavaScript behavior of a webpage, and using
this unique representation to train a classifier for identifying advertising
and tracking resources. Because AdGraph considers many aspects of the context a
network request takes place in, it is less susceptible to the single-factor
evasion techniques that flummox existing approaches.
We evaluate AdGraph on the Alexa top-10K websites, and find that it is highly
accurate, able to replicate the labels of human-generated filter lists with
95.33% accuracy, and can even identify many mistakes in filter lists. We
implement AdGraph as a modification to Chromium. AdGraph adds only minor
overhead to page loading and execution, and is actually faster than stock
Chromium on 42% of websites and AdBlock Plus on 78% of websites. Overall, we
conclude that AdGraph is both accurate enough and performant enough for online
use, breaking comparable or fewer websites than popular filter list based
approaches.
| arxiv topic:cs.CY cs.LG |
arxiv_dataset-98231805.09255 | Cache-Aware QoE-Traffic Optimization in Mobile Edge Assisted Adaptive
Video Streaming
cs.NI
Multi-access edge computing (MEC) enables placing video content at the edge
of the network aiming to improve the quality of experience (QoE) of the mobile
clients. Video content caching at edge servers also reduces traffic in the
backhaul of the mobile network, hence reducing operational costs for mobile
network operators (MNOs). However, minimizing the rate of cache misses and
maximizing the average video quality may sometimes be at odds with each other,
particularly when the cache size is constrained. Our objective in this article
is two fold: First, we explore the impact of fixed video content caching on the
optimal QoE of mobile clients in a setup where servers at mobile network edge
handle bitrate selection. Second, we want to investigate the effect of cache
replacement on QoE-traffic trade-off. An integer nonlinear programming (INLP)
optimization model is formulated for the problem of jointly maximizing the QoE,
the fairness as well as minimizing overall data traffic on the origin video
server. Due to its NP-Hardness, we then present a low complexity greedy-based
algorithm with minimum need for parameter tuning which can be easily deployed.
We show through simulations that the joint optimization indeed enables striking
a desired trade-off between traffic reduction and QoE. The results also reveal
that with fixed cached contents, the impact of caching on the QoE is
proportional to the desired operational point of MNO. Furthermore, the effect
of cache replacement on QoE is less noticeable compared to its effect on
backhaul traffic when cache size is constrained.
| arxiv topic:cs.NI |
arxiv_dataset-98241805.09355 | Scoring Lexical Entailment with a Supervised Directional Similarity
Network
cs.CL cs.LG cs.NE
We present the Supervised Directional Similarity Network (SDSN), a novel
neural architecture for learning task-specific transformation functions on top
of general-purpose word embeddings. Relying on only a limited amount of
supervision from task-specific scores on a subset of the vocabulary, our
architecture is able to generalise and transform a general-purpose
distributional vector space to model the relation of lexical entailment.
Experiments show excellent performance on scoring graded lexical entailment,
raising the state-of-the-art on the HyperLex dataset by approximately 25%.
| arxiv topic:cs.CL cs.LG cs.NE |
arxiv_dataset-98251805.09455 | On BPS World Volume, RR Couplings and their $\alpha'$ Corrections in
type IIB
hep-th gr-qc hep-ph
We compute the asymmetric and symmetric correlation functions of a four point
amplitude of a gauge field, a scalar field and a closed string Ramond-Ramond
(RR) for different non-vanishing BPS branes. All world volume, Taylor and
pull-back couplings and their all order $\alpha'$ corrections have also been
explored. Due to various symmetry structures, different restricted BPS Bianchi
identities have also been constructed. The prescription of exploring all the
corrections of two closed string RR couplings in type IIB is given. We obtain
the closed form of the entire S-matrix elements of two closed string RR and a
gauge field on the world volume of BPS branes in type IIB.
All the correlation functions of $<
V_{A^{0}(x_1)}V_{C^{-1}(z_1,\bar{z}_1)}V_{C^{-1}(z_2,\bar{z}_2)}>$ are also
revealed accordingly. The algebraic forms for the most general case of the
integrations $\int d^2z |z-i|^{a} |z+i|^{b} (z - \bar{z})^{c} (z +
\bar{z})^{d}$ on upper half plane are derived in terms of Pochhammer and some
analytic functions. Lastly, we generate various singularity structures in both
effective field theory and IIB string theory, producing different contact
interactions as well as their $\alpha'$ higher derivative corrections.
| arxiv topic:hep-th gr-qc hep-ph |
arxiv_dataset-98261805.09555 | Phase Retrieval via Polytope Optimization: Geometry, Phase Transitions,
and New Algorithms
cs.IT math.IT
We study algorithms for solving quadratic systems of equations based on
optimization methods over polytopes. Our work is inspired by a recently
proposed convex formulation of the phase retrieval problem, which estimates the
unknown signal by solving a simple linear program over a polytope constructed
from the measurements. We present a sharp characterization of the
high-dimensional geometry of the aforementioned polytope under Gaussian
measurements. This characterization allows us to derive asymptotically exact
performance guarantees for PhaseMax, which also reveal a phase transition
phenomenon with respect to its sample complexity. Moreover, the geometric
insights gained from our analysis lead to a new nonconvex formulation of the
phase retrieval problem and an accompanying iterative algorithm, which we call
PhaseLamp. We show that this new algorithm has superior recovery performance
over the original PhaseMax method. Finally, as yet another variation on the
theme of performing phase retrieval via polytope optimization, we propose a
weighted version of PhaseLamp and demonstrate, through numerical simulations,
that it outperforms several state-of-the-art algorithms under both generic
Gaussian measurements as well as more realistic Fourier-type measurements that
arise in phase retrieval applications.
| arxiv topic:cs.IT math.IT |
arxiv_dataset-98271805.09655 | Global-Locally Self-Attentive Dialogue State Tracker
cs.CL cs.AI
Dialogue state tracking, which estimates user goals and requests given the
dialogue context, is an essential part of task-oriented dialogue systems. In
this paper, we propose the Global-Locally Self-Attentive Dialogue State Tracker
(GLAD), which learns representations of the user utterance and previous system
actions with global-local modules. Our model uses global modules to share
parameters between estimators for different types (called slots) of dialogue
states, and uses local modules to learn slot-specific features. We show that
this significantly improves tracking of rare states and achieves
state-of-the-art performance on the WoZ and DSTC2 state tracking tasks. GLAD
obtains 88.1% joint goal accuracy and 97.1% request accuracy on WoZ,
outperforming prior work by 3.7% and 5.5%. On DSTC2, our model obtains 74.5%
joint goal accuracy and 97.5% request accuracy, outperforming prior work by
1.1% and 1.0%.
| arxiv topic:cs.CL cs.AI |
arxiv_dataset-98281805.09755 | Microreversibility, nonequilibrium current fluctuations, and response
theory
cond-mat.stat-mech
Microreversibility rules the fluctuations of the currents flowing across open
systems in nonequilibrium (or equilibrium) steady states. As a consequence, the
statistical cumulants of the currents and their response coefficients at
arbitrary orders in the deviations from equilibrium obey time-reversal symmetry
relations. It is shown that these relations allow us to systematically reduce
the amount of independent quantities that need to be measured experimentally or
computed theoretically in order to fully characterize the linear and nonlinear
transport properties of general open systems. This reduction is shown to
approach one half for quantities of arbitrarily high orders.
| arxiv topic:cond-mat.stat-mech |
arxiv_dataset-98291805.09855 | MINLO t-channel single-top plus jet
hep-ph
We present a next-to-leading order accurate simulation of t-channel
single-top plus jet production matched to parton showers via the POWHEG method.
The calculation underlying the simulation is enhanced with a process-specific
implementation of the multi-scale improved NLO (MINLO) method, such that it
gives physical predictions all through phase space, including regions where the
jet additional to the t-channel single-top process is unresolved. We further
describe a tuning procedure for the MINLO Sudakov form factor, fitting the
coefficient of the first subleading term in its exponent using an artificial
neural-network. The latter tuning, implemented as a straightforward
event-by-event reweighting, renders the MINLO simulation NLO accurate for
t-channel single-top observables, in addition to those of the analogous
single-top plus jet process.
| arxiv topic:hep-ph |
arxiv_dataset-98301805.09955 | Continuous-stage Runge-Kutta methods based on weighted orthogonal
polynomials
math.NA
We develop continuous-stage Runge-Kutta methods based on weighted orthogonal
polynomials in this paper. There are two main highlighted merits for developing
such methods: Firstly, we do not need to study the tedious solution of
multi-variable nonlinear algebraic equations associated with order conditions;
Secondly, the well-known weighted interpolatory quadrature theory appeared in
every numerical analysis textbook can be directly and conveniently used. By
introducing weight function, various orthogonal polynomials can be used in the
construction of Runge-Kutta-type methods. It turns out that new families of
Runge-Kutta-type methods with special properties (e.g., symplectic, symmetric
etc.) can be constructed in batches, and hopefully it may produce new
applications in numerical ordinary differential equations.
| arxiv topic:math.NA |
arxiv_dataset-98311805.10055 | Parabolicity criteria and characterization results for submanifolds of
bounded mean curvature in model manifolds with weights
math.DG math.AP
Let $P$ be a submanifold properly immersed in a rotationally symmetric
manifold having a pole and endowed with a weight $e^h$. The aim of this paper
is twofold. First, by assuming certain control on the $h$-mean curvature of
$P$, we establish comparisons for the $h$-capacity of extrinsic balls in $P$,
from which we deduce criteria ensuring the $h$-parabolicity or
$h$-hyperbolicity of $P$. Second, we employ functions with geometric meaning to
describe submanifolds of bounded $h$-mean curvature which are confined into
some regions of the ambient manifold. As a consequence, we derive half-space
and Bernstein-type theorems generalizing previous ones. Our results apply for
some relevant $h$-minimal submanifolds appearing in the singularity theory of
the mean curvature flow.
| arxiv topic:math.DG math.AP |
arxiv_dataset-98321805.10155 | Bistability of a slow mechanical oscillator coupled to a laser-driven
two-level system
cond-mat.mes-hall quant-ph
It has been recently proposed that single molecule spectroscopy could be
employed to detect the motion of nano-mechanical resonators. Estimates of the
coupling constant (g) between the molecular two-level system and the oscillator
indicate that it can reach values much larger than the mechanical resonating
pulsation (omega_m) and the two-level system linewidth (Gamma). Other
experimental realization of the same system are also approching this strong
coupling regim. In this paper we investigate the behavior of the system in the
limit for slow mechanical oscillator omega_m << Gamma}. We find that, for
sufficiently large coupling, the system undergoes a bistability reminiscent of
that observed in optical cavities coupled to mechanical resonators.
| arxiv topic:cond-mat.mes-hall quant-ph |
arxiv_dataset-98331805.10255 | Parallel Architecture and Hyperparameter Search via Successive Halving
and Classification
cs.CV cs.AI cs.LG cs.NE
We present a simple and powerful algorithm for parallel black box
optimization called Successive Halving and Classification (SHAC). The algorithm
operates in $K$ stages of parallel function evaluations and trains a cascade of
binary classifiers to iteratively cull the undesirable regions of the search
space. SHAC is easy to implement, requires no tuning of its own configuration
parameters, is invariant to the scale of the objective function and can be
built using any choice of binary classifier. We adopt tree-based classifiers
within SHAC and achieve competitive performance against several strong
baselines for optimizing synthetic functions, hyperparameters and
architectures.
| arxiv topic:cs.CV cs.AI cs.LG cs.NE |
arxiv_dataset-98341805.10355 | What Face and Body Shapes Can Tell About Height
cs.CV
Recovering a person's height from a single image is important for virtual
garment fitting, autonomous driving and surveillance, however, it is also very
challenging due to the absence of absolute scale information. We tackle the
rarely addressed case, where camera parameters and scene geometry is unknown.
To nevertheless resolve the inherent scale ambiguity, we infer height from
statistics that are intrinsic to human anatomy and can be estimated from images
directly, such as articulated pose, bone length proportions, and facial
features. Our contribution is twofold. First, we experiment with different
machine learning models to capture the relation between image content and human
height. Second, we show that performance is predominantly limited by dataset
size and create a new dataset that is three magnitudes larger, by mining
explicit height labels and propagating them to additional images through face
recognition and assignment consistency. Our evaluation shows that monocular
height estimation is possible with a MAE of 5.56cm.
| arxiv topic:cs.CV |
arxiv_dataset-98351805.10455 | Cosmological backreaction and its dependence on spacetime foliation
gr-qc astro-ph.CO hep-th
The subject of cosmological backreaction in General Relativity is often
approached by coordinate-dependent and metric-based analyses. We present in
this letter an averaging formalism for the scalar parts of Einstein's equations
that is coordinate-independent and only functionally depends on a metric. This
formalism is applicable to general 3+1 foliations of spacetime for an arbitrary
fluid with tilted flow. We clarify the dependence on spacetime foliation and
argue that this dependence is weak in cosmological settings. We also introduce
a new set of averaged equations that feature a global cosmological time despite
the generality of the setting, and we put the statistical nature of effective
cosmologies into perspective.
| arxiv topic:gr-qc astro-ph.CO hep-th |
arxiv_dataset-98361805.10555 | Molecular dynamics studies of interaction between asphaltenes and
solvents
physics.chem-ph
Understanding of the molecular interaction between asphaltenes and other
molecules, which may act as its solvents, provides insights into the nature of
its stability in petroleum fluids and its phase transitions. Molecular dynamics
simulations were performed and reported here on systems consisting of a single
asphaltene molecule and pure solvents. Three types of asphaltenes with
different architectures, molecular weights, and heteroatoms content were
investigated. Water and ortho-xylene were selected to be the interacting
solvents. All simulations were performed by using GROMACS software. OPLS_AA
potential model for hydrocarbons and SPC/E potential model for water were used
in simulations. It was shown that the polar functional groups in asphaltenes
were responsible for generating hydrogen bonds (HBs) between asphaltenes and
water. It was also demonstrated that both electrostatic (ES) and van der Waals
(vdW) interaction energies between asphaltenes and water had important roles.
On the contrary, ES between asphaltenes and ortho-xylene had a minor effect as
compared with the vdW. In all cases, potential energies increased rather
slightly when the pressure was boosted. Moreover, they decreased noticeably
when the temperature was raised. HBs between asphaltenes and water were not
influenced by pressure change. Additionally, they increased slightly when the
temperature was dropped.
| arxiv topic:physics.chem-ph |
arxiv_dataset-98371805.10655 | On Late Time Tails in an Extreme Reissner-Nordstr\"om Black Hole:
Frequency Domain Analysis
gr-qc hep-th
In this brief note, we revisit the study of the leading order late time decay
tails of massless scalar perturbations outside an extreme Reissner-Nordstr\"om
black hole. Previous authors have analysed this problem in the time domain; we
analyse the problem in the frequency domain. We first consider initial
perturbations with generic regular behaviour across the horizon on
characteristic surfaces. For this set-up, we reproduce some of the previous
results of Sela [arXiv:1510.06169] using Fourier methods. Next, we consider
related initial data on $t=\mbox{const}$ hypersurfaces, and present decay
results at timelike infinity, near future null infinity, and near the future
horizon. Along the way, using the $r_* \to -r_*$ inversion symmetry of the
extreme Reissner-Nordstr\"om spacetime, we relate the higher multipole Aretakis
and Newman-Penrose constants for a massless scalar in this background.
| arxiv topic:gr-qc hep-th |
arxiv_dataset-98381805.10755 | Dual Policy Iteration
cs.LG stat.ML
Recently, a novel class of Approximate Policy Iteration (API) algorithms have
demonstrated impressive practical performance (e.g., ExIt from [2],
AlphaGo-Zero from [27]). This new family of algorithms maintains, and
alternately optimizes, two policies: a fast, reactive policy (e.g., a deep
neural network) deployed at test time, and a slow, non-reactive policy (e.g.,
Tree Search), that can plan multiple steps ahead. The reactive policy is
updated under supervision from the non-reactive policy, while the non-reactive
policy is improved with guidance from the reactive policy. In this work we
study this Dual Policy Iteration (DPI) strategy in an alternating optimization
framework and provide a convergence analysis that extends existing API theory.
We also develop a special instance of this framework which reduces the update
of non-reactive policies to model-based optimal control using learned local
models, and provides a theoretically sound way of unifying model-free and
model-based RL approaches with unknown dynamics. We demonstrate the efficacy of
our approach on various continuous control Markov Decision Processes.
| arxiv topic:cs.LG stat.ML |
arxiv_dataset-98391805.10855 | Kinetic energy densities based on the fourth order gradient expansion:
performance in different classes of materials and improvement via machine
learning
physics.comp-ph cond-mat.mtrl-sci
We study the performance of fourth-order gradient expansions of the kinetic
energy density (KED) in semi-local kinetic energy functionals depending on the
density-dependent variables. The formal fourth-order expansion is convergent
for periodic systems and small molecules but does not improve over the
second-order expansion (Thomas-Fermi term plus one-ninth of von Weizs\"acker
term). Linear fitting of the expansion coefficients somewhat improves on the
formal expansion. The tuning of the fourth order expansion coefficients allows
for better reproducibility of Kohn-Sham kinetic energy density than the tuning
of the second-order expansion coefficients alone. The possibility of a much
more accurate match with the Kohn-Sham kinetic energy density by using neural
networks trained using the terms of the 4th order expansion as
density-dependent variables is demonstrated. We obtain ultra-low fitting errors
without overfitting. Small single hidden layer neural networks can provide good
accuracy in separate KED fits of each compound, while for joint fitting of KEDs
of multiple compounds multiple hidden layers were required to achieve good fit
quality. The critical issue of data distribution is highlighted. We also show
the critical role of pseudopotentials in the performance of the expansion,
where in the case of a too rapid decay of the valence density at the nucleus
with some pseudopotentials, numeric instabilities arise.
| arxiv topic:physics.comp-ph cond-mat.mtrl-sci |
arxiv_dataset-98401805.10955 | Propagation of solutions of the Porous Medium Equation with reaction and
their travelling wave behaviour
math.AP
We consider reaction-diffusion equations of porous medium type, with
different kind of reaction terms, and nonnegative bounded initial data. For all
the reaction terms under consideration there are initial data for which the
solution converges to 1 uniformly in compact sets for large times. We will
characterize for which reaction terms this happens for all nontrivial
nonnegative initial data, and for which ones there are also solutions
converging uniformly to 0. Problems in this family have a unique (up to
translations) travelling wave with a finite front and we will see how its speed
gives the asymptotic velocity of all the solutions with compactly supported
initial data. We will also prove in the one-dimensional case that solutions
with bounded compactly supported initial data converging to 1 do so approaching
a translation of this unique traveling wave. We will prove a similar result for
non-compactly supported initial data in a certain class.
| arxiv topic:math.AP |
arxiv_dataset-98411805.11055 | Local properties of the surface measure of convex bodies
math.MG
It is well known that any measure in S^2 satisfying certain simple conditions
is the surface measure of a bounded convex body in R^3. It is also known that a
local perturbation of the surface measure may lead to a nonlocal perturbation
of the corresponding convex body. We prove that, under mild conditions on a
convex body, there are families of perturbations of its surface measure forming
line segments, with the original measure at the midpoint, leading to local
perturbations of the body. Moreover, there is, in a sense, a huge amount of
such families. We apply this result to Newton's problem of minimal resistance
for convex bodies.
| arxiv topic:math.MG |
arxiv_dataset-98421805.11155 | Unsupervised Learning of Artistic Styles with Archetypal Style Analysis
stat.ML cs.CV cs.LG
In this paper, we introduce an unsupervised learning approach to
automatically discover, summarize, and manipulate artistic styles from large
collections of paintings. Our method is based on archetypal analysis, which is
an unsupervised learning technique akin to sparse coding with a geometric
interpretation. When applied to deep image representations from a collection of
artworks, it learns a dictionary of archetypal styles, which can be easily
visualized. After training the model, the style of a new image, which is
characterized by local statistics of deep visual features, is approximated by a
sparse convex combination of archetypes. This enables us to interpret which
archetypal styles are present in the input image, and in which proportion.
Finally, our approach allows us to manipulate the coefficients of the latent
archetypal decomposition, and achieve various special effects such as style
enhancement, transfer, and interpolation between multiple archetypes.
| arxiv topic:stat.ML cs.CV cs.LG |
arxiv_dataset-98431805.11255 | Succinct data structure for dynamic trees with faster queries
cs.DS
Navarro and Sadakane [TALG 2014] gave a dynamic succinct data structure for
storing an ordinal tree. The structure supports tree queries in either $O(\log
n/\log\log n)$ or $O(\log n)$ time, and insertion or deletion of a single node
in $O(\log n)$ time. In this paper we improve the result of Navarro and
Sadakane by reducing the time complexities of some queries (e.g.\ degree and
level\_ancestor) from $O(\log n)$ to $O(\log n/\log\log n)$.
| arxiv topic:cs.DS |
arxiv_dataset-98441805.11355 | Authentication protocol based on collective quantum steering
quant-ph
It is well known that certain quantum correlations like quantum steering
exhibit a monogamous relationship. In this paper, we exploit the asymmetric
nature of quantum steering and show that there exist states which exhibit a
polygamous correlation, known as collective correlation [He and Reid, Phys.
Rev. Lett. 111, 250403 (2013)], where the state of one party, Alice, can be
steered only by the joint effort of the other two parties, Bob and Charlie. As
an example, we explicitly single out a particular set of $3$ qubit states which
exhibit this polygamous relationship, known as collective steerability. We
provide a recipe to identify the complete set of such states. We also provide a
possible application of such states to an information theoretic task, termed as
quantum key authentication (QKA) protocol. QKA can also be used in conjunction
with other well known cryptography protocols to improve their security and we
provide one such example with quantum private comparison (QPC).
| arxiv topic:quant-ph |
arxiv_dataset-98451805.11455 | The Mid-Frequency Square Kilometre Array Phase Synchronisation System
astro-ph.IM
This paper describes the technical details and practical implementation of
the Mid-Frequency Square Kilometre Array (SKA) phase synchronisation system.
Over a four-year period, the system has been tested on metropolitan fibre-optic
networks, on long-haul overhead fibre at the South African SKA site, and on
existing telescopes in Australia to verify its functional performance. The
tests have shown that the system exceed the 1-second SKA coherence loss
requirement by a factor 2560, the 60-second coherence loss requirement by a
factor of 239, and the 10-minute phase drift requirement by almost five
orders-of-magnitude. The paper also reports on tests showing that the system
can operate within specification over the all required operating conductions,
including maximum fibre link distance, temperature range, temperature gradient,
relative humidity, wind speed, seismic resilience, electromagnetic compliance,
frequency offset, and other operational requirements.
| arxiv topic:astro-ph.IM |
arxiv_dataset-98461805.11555 | Optimisation and Illumination of a Real-world Workforce Scheduling and
Routing Application via Map-Elites
cs.AI
Workforce Scheduling and Routing Problems (WSRP) are very common in many
practical domains, and usually, have a number of objectives. Illumination
algorithms such as Map-Elites (ME) have recently gained traction in application
to {\em design} problems, in providing multiple diverse solutions as well as
illuminating the solution space in terms of user-defined characteristics, but
typically require significant computational effort to produce the solution
archive. We investigate whether ME can provide an effective approach to solving
WSRP, a {\em repetitive} problem in which solutions have to be produced quickly
and often. The goals of the paper are two-fold. The first is to evaluate
whether ME can provide solutions of competitive quality to an Evolutionary
Algorithm (EA) in terms of a single objective function, and the second to
examine its ability to provide a repertoire of solutions that maximise user
choice. We find that very small computational budgets favour the EA in terms of
quality, but ME outperforms the EA at larger budgets, provides a more diverse
array of solutions, and lends insight to the end-user.
| arxiv topic:cs.AI |
arxiv_dataset-98471805.11655 | Some generalizations of frames in Hilbert modules
math.OA math.FA
Frames play significant role in various areas of science and engineering. In
this paper, we introduce the concepts of frames for
$End_{\mathcal{A}}^{\ast}(\mathcal{H, K})$ and their generalizations. Moreover,
we obtain some new results for generalized frames in Hilbert modules.
| arxiv topic:math.OA math.FA |
arxiv_dataset-98481805.11755 | Collisional Disruption of Planetesimals in the Gravity Regime with iSALE
Code: Comparison with SPH code for Purely Hydrodynamic Bodies
astro-ph.EP
In most of the previous studies related to collisional disruption of
planetesimals in the gravity regime, Smoothed Particle Hydrodynamics (SPH)
simulations have been used. On the other hand, impact simulations using
grid-based hydrodynamic code have not been sufficiently performed. In the
present study, we execute impact simulations in the gravity regime using the
shock-physics code iSALE, which is a grid-based Eulerian hydrocode. We examine
the dependence of the critical specific impact energy Q_RD* on impact
conditions for a wide range of specific impact energy (Q_R) from disruptive
collisions to erosive collisions, and compare our results with previous
studies. We find collision outcomes of the iSALE simulation agree well with
those of the SPH simulation. Detailed analysis mainly gives three results. (1)
The value of Q_RD* depends on numerical resolution, and is close to convergence
with increasing numerical resolution. The difference in converged value of
Q_RD* between the iSALE code and the SPH code is within 30%. (2) Ejected mass
normalized by total mass (M_ej/M_tot) generally depends on various impact
conditions. However, when Q_R is normalized by Q_RD* that is calculated for
each impact simulation, M_ej/M_tot can be scaled by Q_R/Q_RD*, and is
independent of numerical resolution, impact velocity and target size. (3) This
similarity law for Q_R/Q_RD* is confirmed for a wide range of specific impact
energy. We also derive a semi-analytic formula for Q_RD* based on the
similarity law and the crater scaling law. We find that the semi-analytic
formula for the case with a non-porous object is consistent with numerical
results.
| arxiv topic:astro-ph.EP |
arxiv_dataset-98491805.11855 | Rational extension of Newton diagram for the positivity of ${}_1F_2$
hypergeometric functions and Askey-Szeg\"o problem
math.CA
We present a rational extension of Newton diagram for the positivity of
${}_1F_2$ generalized hypergeometric functions. As an application, we give
upper and lower bounds for the transcendental roots $\beta(\alpha)$ of
\begin{align*} \int_0^{j_{\alpha, 2}} t^{-\beta} J_\alpha(t) dt =
0\qquad(-1<\alpha\le 1/2), \end{align*} where $j_{\alpha, 2}$ denotes the
second positive zero of Bessel function $J_\alpha$.
| arxiv topic:math.CA |
arxiv_dataset-98501805.11955 | Simplicity of algebras via epsilon-strong systems
math.RA
We obtain sufficient criteria for simplicity of systems, that is, rings $R$
that are equipped with a family of additive subgroups $R_s$, for $s \in S$,
where $S$ is a semigroup, satisfying $R = \sum_{s \in S} R_s$ and $R_s R_t
\subseteq R_{st}$, for $s,t \in S$. These criteria are specialized to obtain
sufficient criteria for simplicity of, what we call, s-unital epsilon-strong
systems, that is systems where $S$ is an inverse semigroup, $R$ is coherent, in
the sense that for all $s,t \in S$ with $s \leq t$, the inclusion $R_s
\subseteq R_t$ holds, and for each $s \in S$, the $R_s
R_{s^*}$-$R_{s^*}R_s$-bimodule $R_s$ is s-unital. As an aplication of this, we
obtain generalizations of recent criteria for simplicity of skew inverse
semigroup rings, by Beuter, Goncalves, \"{O}inert and Royer, and then, in turn,
for Steinberg algebras, over non-commutative rings, by Brown, Farthing, Sims,
Steinberg, Clark and Edie-Michel.
| arxiv topic:math.RA |
arxiv_dataset-98511805.12055 | Extragalactic photon--axion-like particle oscillations up to 1000 TeV
astro-ph.HE hep-ph
Axion-like particles (ALPs) are attracting increasing interest since, among
other things, they are a prediction of many extensions of the standard model of
elementary particles physics and in particular of superstrings and superbranes.
Remarkably, depending on the set of their parameter space, they strongly
increase the photon transparency in the very-high energy band. The recent
discovery of photon dispersion on the CMB requires a substantial modification
of the previous picture: this is indeed the goal of the present paper. We
compute the photon survival probability from a blazar to us exactly, and we
plot it versus the observed energy for 7 simulated blazars at different $z$ and
4 values of a model parameter. Our predictions can be tested by the new
generation of $\gamma$-ray observatories like CTA, HAWC, GAMMA-400, LHAASO,
TAIGA-HiSCORE and HERD. Finally, for our guessed values of $m_a$ and $g_{\gamma
\gamma a}$ our ALP can be detected in the upgrade of ALPS II at DESY, the
planned experiments IAXO, STAX and ABRACADABRA as well as with other
techniques.
| arxiv topic:astro-ph.HE hep-ph |
arxiv_dataset-98521805.12155 | The plane-wave spectrum from the worldsheet
hep-th
We study string theory on $\mathrm{AdS}_3$ backgrounds with mixed flux using
the hybrid formalism of Berkovits, Vafa and Witten. We solve the worldsheet
description of the theory completely in the plane-wave limit. This constitutes
a direct derivation of the plane-wave spectrum from the worldsheet with mixed
flux.
| arxiv topic:hep-th |
arxiv_dataset-98531805.12255 | Bose-Einstein condensation of alpha clusters and new soft mode in
12C--52Fe 4N nuclei in field theoretical superfluid cluster model
nucl-th
Bose-Einstein condensation of alpha clusters in light and medium-heavy nuclei
is studied in the frame of the field theoretical superfluid cluster model. The
order parameter of the phase transition from the Wigner phase to the
Nambu-Goldstone phase is a superfluid amplitude, square of the moduli of which
is the superfluid density distribution. The zero mode operators due to the
spontaneous symmetry breaking of the global phase in the finite number of alpha
clusters are rigorously treated. The theory is systematically applied to N
alpha nuclei from12C-52Fe at various condensation rates. In 12C it is found
that the energy levels of the gas-like well-developed alpha cluster states
above the Hoyle state are reproduced well in agreement with experiment for
realistic condensation rates of alpha clusters. The electric E2 and E0
transitions are calculated and found to be sensitive to the condensation rates.
The profound raison d'etre of the alpha cluster gas-like states above the Hoyle
state, whose structure has been interpreted geometrically in the nuclear models
without the order parameter such as the cluster models or ab initio
calculations, is revealed. It is found that in addition to the Bogoliubov-de
Gennes vibrational mode states collective states of the zero mode operators
appear systematically at low excitation energies from the N alpha threshold
energy. These collective states, new-type soft modes in nuclei due to the
Bose-Einstein condensation of the alpha clusters, emerge systematically in
light and medium-heavy mass regions and are also located at high excitation
energies from the ground state in contrast to the traditional concept of soft
mode in the low excitation energy region.
| arxiv topic:nucl-th |
arxiv_dataset-98541805.12355 | Deep-Energy: Unsupervised Training of Deep Neural Networks
cs.LG stat.ML
The success of deep learning has been due, in no small part, to the
availability of large annotated datasets. Thus, a major bottleneck in current
learning pipelines is the time-consuming human annotation of data. In scenarios
where such input-output pairs cannot be collected, simulation is often used
instead, leading to a domain-shift between synthesized and real-world data.
This work offers an unsupervised alternative that relies on the availability of
task-specific energy functions, replacing the generic supervised loss. Such
energy functions are assumed to lead to the desired label as their minimizer
given the input. The proposed approach, termed "Deep Energy", trains a Deep
Neural Network (DNN) to approximate this minimization for any chosen input.
Once trained, a simple and fast feed-forward computation provides the inferred
label. This approach allows us to perform unsupervised training of DNNs with
real-world inputs only, and without the need for manually-annotated labels, nor
synthetically created data. "Deep Energy" is demonstrated in this paper on
three different tasks -- seeded segmentation, image matting and single image
dehazing -- exposing its generality and wide applicability. Our experiments
show that the solution provided by the network is often much better in quality
than the one obtained by a direct minimization of the energy function,
suggesting an added regularization property in our scheme.
| arxiv topic:cs.LG stat.ML |
arxiv_dataset-98551805.12455 | p-p, p-$\Lambda$ and $\Lambda$-$\Lambda$ correlations studied via
femtoscopy in pp reactions at $\sqrt{s}$ = 7 TeV
nucl-ex hep-ex
We report on the first femtoscopic measurement of baryon pairs, such as p-p,
p-$\Lambda$ and $\Lambda$-$\Lambda$, measured by ALICE at the Large Hadron
Collider (LHC) in proton-proton collisions at $\sqrt{s}$ = 7 TeV. This study
demonstrates the feasibility of such measurements in pp collisions at
ultrarelativistic energies. The femtoscopy method is employed to constrain the
hyperon-nucleon and hyperon-hyperon interactions, which are still rather poorly
understood. A new method to evaluate the influence of residual correlations
induced by the decays of resonances and experimental impurities is hereby
presented. The p-p, p-$\Lambda$ and $\Lambda$-$\Lambda$ correlation functions
were fitted simultaneously with the help of a new tool developed specifically
for the femtoscopy analysis in small colliding systems 'Correlation Analysis
Tool using the Schr\"odinger Equation' (CATS). Within the assumption that in pp
collisions the three particle pairs originate from a common source, its radius
is found to be equal to $r_{0} = 1.125\pm0.018$ (stat) $^{+0.058}_{-0.035}$
(syst) fm. The sensitivity of the measured p-$\Lambda$ correlation is tested
against different scattering parameters which are defined by the interaction
among the two particles, but the statistics is not sufficient yet to
discriminate among different models. The measurement of the $\Lambda$-$\Lambda$
correlation function constrains the phase space spanned by the effective range
and scattering length of the strong interaction. Discrepancies between the
measured scattering parameters and the resulting correlation functions at LHC
and RHIC energies are discussed in the context of various models.
| arxiv topic:nucl-ex hep-ex |
arxiv_dataset-98561805.12555 | The integer quantum Hall plateau transition is a current algebra after
all
math-ph cond-mat.dis-nn hep-th math.MP
The scaling behavior near the transition between plateaus of the Integer
Quantum Hall Effect (IQHE) has traditionally been interpreted on the basis of a
two-parameter renormalization group (RG) flow conjectured from Pruisken's
non-linear sigma model. Yet, the conformal field theory (CFT) describing the
critical point remained elusive, and only fragments of a quantitative
analytical understanding existed up to now. In the present paper we carry out a
detailed analysis of the current-current correlation function for the
conductivity tensor, initially in the Chalker-Coddington network model for the
IQHE plateau transition and then in its exact reformulation as a supersymmetric
vertex model. We develop a heuristic argument for the continuum limit of the
non-local conductivity response function at criticality and thus identify a
non-Abelian current algebra at level n = 4. Based on precise lattice
expressions for the CFT primary fields we predict the multifractal scaling
exponents of critical wavefunctions to be q(1-q)/4. The Lagrangian of the RG
fixed-point theory for r retarded and r advanced replicas is proposed to be the
GL(r|r)_4 Wess-Zumino-Witten model deformed by a truly marginal perturbation.
The latter emerges from the non-linear sigma model by a natural scenario of
spontaneous symmetry breaking.
| arxiv topic:math-ph cond-mat.dis-nn hep-th math.MP |
arxiv_dataset-98571806.0006 | The Mullins effect in the wrinkling behavior of highly stretched thin
films
cond-mat.soft
Recent work demonstrates that finite-deformation nonlinear elasticity is
essential in the accurate modeling of wrinkling in highly stretched thin films.
Geometrically exact models predict an isola-center bifurcation, indicating that
for a bounded interval of aspect ratios only, stable wrinkles appear and then
disappear as the macroscopic strain is increased. This phenomenon has been
verified in experiments. In addition, recent experiments revealed the following
striking phenomenon: For certain aspect ratios for which no wrinkling occurred
upon the first loading, wrinkles appeared during the first unloading and again
during all subsequent cyclic loading. Our goal here is to present a simple
pseudo-elastic model, capturing the stress softening and residual strain
observed in the experiments, that accurately predicts wrinkling behavior on the
first loading that differs from that under subsequent cyclic loading. In
particular for specific aspect ratios, the model correctly predicts the
scenario of no wrinkling during first loading with wrinkling occurring during
unloading and for all subsequent cyclic loading.
| arxiv topic:cond-mat.soft |
arxiv_dataset-98581806.0016 | Sparse Multiband Signal Acquisition Receiver with Co-prime Sampling
eess.SP cs.IT math.IT
Cognitive radio (CR) requires spectrum sensing over a broad frequency band.
One of the crucial tasks in CR is to sample wideband signal at high sampling
rate. In this paper, we propose an acquisition receiver with co-prime sampling
technique for wideband sparse signals, which occupy a small part of band range.
In this proposed acquisition receiver, we use two low speed analog-to-digital
converters (ADCs) to capture a common sparse multiband signal, whose band
locations are unknown. The two ADCs are synchronously clocked at co-prime
sampling rates. The obtained samples are re-sequenced into a group of uniform
sequences with low rate. We derive the mathematical model for the receiver in
the frequency domain and present its signal reconstruction algorithm. Compared
to the existing sub-Nyquist sampling techniques, such as multi-coset sampling
and modulated wideband converter, the proposed approach has a simple system
architecture and can be implemented with only two samplers. Experimental
results are reported to demonstrate the feasibility and advantage of the
proposed model. For sparse multiband signal with unknown spectral support, the
proposed system requires a sampling rate much lower than Nyquist rate, while
produces satisfactory reconstruction.
| arxiv topic:eess.SP cs.IT math.IT |
arxiv_dataset-98591806.0026 | The Proximal Alternating Minimization Algorithm for two-block separable
convex optimization problems with linear constraints
math.OC math.NA
The Alternating Minimization Algorithm (AMA) has been proposed by Tseng to
solve convex programming problems with two-block separable linear constraints
and objectives, whereby (at least) one of the components of the latter is
assumed to be strongly convex. The fact that one of the subproblems to be
solved within the iteration process of AMA does not usually correspond to the
calculation of a proximal operator through a closed formula, affects the
implementability of the algorithm. In this paper we allow in each block of the
objective a further smooth convex function and propose a proximal version of
AMA, called Proximal AMA, which is achieved by equipping the algorithm with
proximal terms induced by variable metrics. For suitable choices of the latter,
the solving of the two subproblems in the iterative scheme can be reduced to
the computation of proximal operators. We investigate the convergence of the
proposed algorithm in a real Hilbert space setting and illustrate its numerical
performances on two applications in image processing and machine learning.
| arxiv topic:math.OC math.NA |
arxiv_dataset-98601806.0036 | Towards a new system for drowsiness detection based on eye blinking and
head posture estimation
cs.CV eess.IV
Driver drowsiness problem is considered as one of the most important reasons
that increases road accidents number. We propose in this paper a new approach
for realtime driver drowsiness in order to prevent road accidents. The system
uses a smart video camera that takes drivers faces images and supervises the
eye blink (open and close) state and head posture to detect the different
drowsiness states. Face and eye detection are done by Viola and Jones
technique.
| arxiv topic:cs.CV eess.IV |
arxiv_dataset-98611806.0046 | Assessing Perturbativity and Vacuum Stability in High-Scale Leptogenesis
hep-ph
We consider the requirements that all coupling constants remain perturbative
and the electroweak vacuum metastable up to the Planck scale in high-scale
thermal leptogenesis, in the context of a type-I seesaw mechanism. We find a
large region of the model parameter space that satisfies these conditions in
combination with producing the baryon asymmetry of the Universe. We demonstrate
these conditions require ${\rm Tr}[Y_N^\dagger Y_N] \lesssim 0.66$ on the
neutrino Yukawa matrix. We also investigate this scenario in the presence of a
large number $N_F$ of coloured Majorana octet fermions in order to make quantum
chromodynamics asymptotically safe in the ultraviolet.
| arxiv topic:hep-ph |
arxiv_dataset-98621806.0056 | High-dimensional measurement-device-independent quantum key distribution
based on spatial basis
physics.optics
Improving the secret key rate is one of the vital issues in practical
applications of quantum key distribution (QKD). In this paper, we propose an
experimental scheme of high-dimensional measurement-device-independent quantum
key distribution (MDI-QKD) based on spatial basis aiming to increase the key
rate. Two groups of discrete position basis and momentum basis are applied as
conjugate spaces to generate quantum secret key. The position states are
transmitted by single-mode fibers and represented by the index of the fiber,
while the momentum state is a coherent superposition of the position states
characterized by the phase gradient. The measurement of each momentum basis is
realized by multi-slit diffraction. This experimental proposal can be
implemented with standard optical elements. In addition to an enhanced key rate
in a higher dimension, this high-dimensional MDI-QKD exhibits a comparable
security level/performance compared to conventional polarization-based MDI-QKD.
| arxiv topic:physics.optics |
arxiv_dataset-98631806.0066 | Flavourful Axion Phenomenology
hep-ph
We present a comprehensive discussion of the phenomenology of flavourful
axions, including both standard Peccei-Quinn (PQ) axions, associated with the
solution to the strong $CP$ problem, and non-standard axion-like particles
(ALPs). We give the flavourful axion-fermion and axion-photon couplings and
calculate the branching ratios of heavy meson ($K$, $D$, $B$) decays involving
a flavourful axion. We also calculate the mixing between axions and heavy
mesons $ K^0 $, $ D^0 $, $ B^0 $ and $ B_s^0 $, which affects the meson
oscillation probability and mass difference. Mixing also contributes to meson
decays into axions and axion decays into two photons, and may be relevant for
ALPs. We discuss charged lepton flavour-violating decays involving final state
axions of the form $\ell_1 \to \ell_2 a (\gamma) $, as well as $ \mu \to eee $
and $ \mu-e $ conversion. Finally we describe the phenomenology of a particular
"A to Z" Pati-Salam model, in which PQ symmetry arises accidentally due to
discrete flavour symmetry. Here all axion couplings are fixed by a fit to
flavour data, leading to sharp predictions and correlations between
flavour-dependent observables.
| arxiv topic:hep-ph |
arxiv_dataset-98641806.0076 | Efficient Time-Evolving Stream Processing at Scale
cs.DC
Time-evolving stream datasets exist ubiquitously in many real-world
applications where their inherent hot keys often evolve over times.
Nevertheless, few existing solutions can provide efficient load balance on
these time-evolving datasets while preserving low memory overhead. In this
paper, we present a novel grouping approach (named FISH), which can provide the
efficient time-evolving stream processing at scale. The key insight of this
work is that the keys of time-evolving stream data can have a skewed
distribution within any bounded distance of time interval. This enables to
accurately identify the recent hot keys for the real-time load balance within a
bounded scope. We therefore propose an epoch-based recent hot key
identification with specialized intra-epoch frequency counting (for maintaining
low memory overhead) and inter-epoch hotness decaying (for suppressing
superfluous computation). We also propose to heuristically infer the accurate
information of remote workers through computation rather than communication for
cost-efficient worker assignment. We have integrated our approach into Apache
Storm. Our results on a cluster of 128 nodes for both synthetic and real-world
stream datasets show that FISH significantly outperforms state-of-the-art with
the average and the 99th percentile latency reduction by 87.12% and 76.34% (vs.
W-Choices), and memory overhead reduction by 99.96% (vs. Shuffle Grouping).
| arxiv topic:cs.DC |
arxiv_dataset-98651806.0086 | Optimizing weighted ensemble sampling of steady states
math.NA cs.NA
We propose parameter optimization techniques for weighted ensemble sampling
of Markov chains in the steady-state regime. Weighted ensemble consists of
replicas of a Markov chain, each carrying a weight, that are periodically
resampled according to their weights inside of each of a number of bins that
partition state space. We derive, from first principles, strategies for
optimizing the choices of weighted ensemble parameters, in particular the
choice of bins and the number of replicas to maintain in each bin. In a simple
numerical example, we compare our new strategies with more traditional ones and
with direct Monte Carlo.
| arxiv topic:math.NA cs.NA |
arxiv_dataset-98661806.0096 | The Capacity Constrained Facility Location problem
cs.GT cs.AI
We initiate the study of the capacity constrained facility location problem
from a mechanism design perspective. The capacity constrained setting leads to
a new strategic environment where a facility serves a subset of the population,
which is endogenously determined by the ex-post Nash equilibrium of an induced
subgame and is not directly controlled by the mechanism designer. Our focus is
on mechanisms that are ex-post dominant-strategy incentive compatible (DIC) at
the reporting stage. We provide a complete characterization of DIC mechanisms
via the family of Generalized Median Mechanisms (GMMs). In general, the social
welfare optimal mechanism is not DIC. Adopting the worst-case approximation
measure, we attain tight lower bounds on the approximation ratio of any DIC
mechanism. The well-known median mechanism is shown to be optimal among the
family of DIC mechanisms for certain capacity ranges. Surprisingly, the
framework we introduce provides a new characterization for the family of GMMs,
and is responsive to gaps in the current social choice literature highlighted
by Border and Jordan (1983) and Barbar{\`a}, Mass{\'o} and Serizawa (1998).
| arxiv topic:cs.GT cs.AI |
arxiv_dataset-98671806.0106 | Sharp multiplier theorem for multidimensional Bessel operators
math.FA
Consider the multidimensional Bessel operator $$B f(x) = -\sum_{j=1}^N
\left(\partial_j^2 f(x) +\frac{\alpha_j}{x_j} \partial_j f(x)\right), \quad
x\in(0,\infty)^N. $$ Let $d = \sum_{j=1}^N \max(1,\alpha_j+1)$ be the
homogeneous dimension of the space $(0,\infty)^N$ equipped with the measure
$x_1^{\alpha_1}... x_N^{\alpha_N} dx_1...dx_N$. In the general case
$\alpha_1,...,\alpha_N >-1$ we prove multiplier theorems for spectral
multipliers $m(B)$ on $L^{1,\infty}$ and the Hardy space $H^1$. We assume that
$m$ satisfies the classical H\"ormander condition $$\sup_{t>0}
\left||\eta(\cdot) m(t\cdot)\right||_{W^{2,\beta}(\mathbb{R})}<\infty$$ with
$\beta > d/2$. Furthermore, we investigate imaginary powers $B^{ib}$, $b\in
\mathbb{R}$, and prove some lower estimates on $L^{1,\infty}$ and $L^p$,
$1<p<2$. As a consequence, we deduce that our multiplier theorem is sharp.
| arxiv topic:math.FA |
arxiv_dataset-98681806.0116 | On effective field theory of F-theory beyond leading order
hep-th
We construct a proposal for effective bosonic field theory at order $
\alpha'^3 $ in twelve dimensions, whose compactification on a circle and on a
torus respectively yields eleven-dimensional and type IIB supergravity theories
at eight-derivative level. The couplings $ ({\partial {G_5}})^2 R^2 $, $
({\partial {F_4}})^2 R^2 $, $ ({\partial {F_4}})^4 $, $ ({\partial {G_5}})^4 $
and $ ({\partial {G_5}})^2({\partial {F_4}})^2 $ in twelve-dimensional
supergravity are determined with this requirement that an ansatz of these
couplings should admits a consistent truncation to the eleven-dimensional and
type IIB supergravity theories. The self-duality condition of the five-form
field strength in twelve dimensions is also understood by considering the RR
five-form field strength of type IIB theory at linear order.
| arxiv topic:hep-th |
arxiv_dataset-98691806.0126 | Digging Into Self-Supervised Monocular Depth Estimation
cs.CV stat.ML
Per-pixel ground-truth depth data is challenging to acquire at scale. To
overcome this limitation, self-supervised learning has emerged as a promising
alternative for training models to perform monocular depth estimation. In this
paper, we propose a set of improvements, which together result in both
quantitatively and qualitatively improved depth maps compared to competing
self-supervised methods.
Research on self-supervised monocular training usually explores increasingly
complex architectures, loss functions, and image formation models, all of which
have recently helped to close the gap with fully-supervised methods. We show
that a surprisingly simple model, and associated design choices, lead to
superior predictions. In particular, we propose (i) a minimum reprojection
loss, designed to robustly handle occlusions, (ii) a full-resolution
multi-scale sampling method that reduces visual artifacts, and (iii) an
auto-masking loss to ignore training pixels that violate camera motion
assumptions. We demonstrate the effectiveness of each component in isolation,
and show high quality, state-of-the-art results on the KITTI benchmark.
| arxiv topic:cs.CV stat.ML |
arxiv_dataset-98701806.0136 | Evaluating Impact of Human Errors on the Availability of Data Storage
Systems
cs.PF cs.DC
In this paper, we investigate the effect of incorrect disk replacement
service on the availability of data storage systems. To this end, we first
conduct Monte Carlo simulations to evaluate the availability of disk subsystem
by considering disk failures and incorrect disk replacement service. We also
propose a Markov model that corroborates the Monte Carlo simulation results. We
further extend the proposed model to consider the effect of automatic disk
fail-over policy. The results obtained by the proposed model show that
overlooking the impact of incorrect disk replacement can result up to three
orders of magnitude unavailability underestimation. Moreover, this study
suggests that by considering the effect of human errors, the conventional
believes about the dependability of different RAID mechanisms should be
revised. The results show that in the presence of human errors, RAID1 can
result in lower availability compared to RAID5.
| arxiv topic:cs.PF cs.DC |
arxiv_dataset-98711806.0146 | Dynamic Function-on-Scalars Regression
stat.ME
We develop a modeling framework for dynamic function-on-scalars regression,
in which a time series of functional data is regressed on a time series of
scalar predictors. The regression coefficient function for each predictor is
allowed to be dynamic, which is essential for applications where the
association between predictors and a (functional) response is time-varying. For
greater modeling flexibility, we design a nonparametric reduced-rank functional
data model with an unknown functional basis expansion, which is data-adaptive
and, unlike most existing methods, modeled as unknown for appropriate
uncertainty quantification. Within a Bayesian framework, we introduce shrinkage
priors that simultaneously (i) regularize time-varying regression coefficient
functions to be locally static, (ii) effectively remove unimportant predictor
variables from the model, and (iii) reduce sensitivity to the dimension of the
functional basis. A simulation analysis confirms the importance of these
shrinkage priors, with notable improvements over existing alternatives. We
develop a novel projection-based Gibbs sampling algorithm, which offers
unrivaled computational scalability for fully Bayesian functional regression.
We apply the proposed methodology (i) to analyze the time-varying impact of
macroeconomic variables on the U.S. yield curve and (ii) to characterize the
effects of socioeconomic and demographic predictors on age-specific fertility
rates in South and Southeast Asia.
| arxiv topic:stat.ME |
arxiv_dataset-98721806.0156 | Sharp quadrature error bounds for the nearest-neighbor discretization of
the regularized stokeslet boundary integral equation
physics.flu-dyn math.NA
The method of regularized stokeslets is a powerful numerical method to solve
the Stokes flow equations for problems in biological fluid mechanics. A recent
variation of this method incorporates a nearest-neighbor discretization to
improve accuracy and efficiency while maintaining the ease-of-implementation of
the original meshless method. This method contains three sources of numerical
error, the regularization error associated from using the regularized form of
the boundary integral equations (with parameter $\varepsilon$), and two sources
of discretization error associated with the force and quadrature
discretizations (with lengthscales $h_f$ and $h_q$). A key issue to address is
the quadrature error: initial work has not fully explained observed numerical
convergence phenomena. In the present manuscript we construct sharp quadrature
error bounds for the nearest-neighbor discretisation, noting that the error for
a single evaluation of the kernel depends on the smallest distance ($\delta$)
between these discretization sets. The quadrature error bounds are described
for two cases: with disjoint sets ($\delta>0$) being close to linear in $h_q$
and insensitive to $\varepsilon$, and contained sets ($\delta=0$) being
quadratic in $h_q$ with inverse dependence on $\varepsilon$. The practical
implications of these error bounds are discussed with reference to the
condition number of the matrix system for the nearest-neighbor method, with the
analysis revealing that the condition number is insensitive to $\varepsilon$
for disjoint sets, and grows linearly with $\varepsilon$ for contained sets.
Error bounds for the general case ($\delta\geq 0$) are revealed to be
proportional to the sum of the errors for each case.
| arxiv topic:physics.flu-dyn math.NA |
arxiv_dataset-98731806.0166 | Towards Understanding Acceleration Tradeoff between Momentum and
Asynchrony in Nonconvex Stochastic Optimization
cs.LG stat.ML
Asynchronous momentum stochastic gradient descent algorithms (Async-MSGD) is
one of the most popular algorithms in distributed machine learning. However,
its convergence properties for these complicated nonconvex problems is still
largely unknown, because of the current technical limit. Therefore, in this
paper, we propose to analyze the algorithm through a simpler but nontrivial
nonconvex problem - streaming PCA, which helps us to understand Aync-MSGD
better even for more general problems. Specifically, we establish the
asymptotic rate of convergence of Async-MSGD for streaming PCA by diffusion
approximation. Our results indicate a fundamental tradeoff between asynchrony
and momentum: To ensure convergence and acceleration through asynchrony, we
have to reduce the momentum (compared with Sync-MSGD). To the best of our
knowledge, this is the first theoretical attempt on understanding Async-MSGD
for distributed nonconvex stochastic optimization. Numerical experiments on
both streaming PCA and training deep neural networks are provided to support
our findings for Async-MSGD.
| arxiv topic:cs.LG stat.ML |
arxiv_dataset-98741806.0176 | Predictive Accuracy of Markers or Risk Scores for Interval Censored
Survival Data
stat.ME
Methods for the evaluation of the predictive accuracy of biomarkers with
respect to survival outcomes subject to right censoring have been discussed
extensively in the literature. In cancer and other diseases, survival outcomes
are commonly subject to interval censoring by design or due to the follow up
schema. In this paper, we present an estimator for the area under the
time-dependent receiver operating characteristic ROC curve for interval
censored data based on a nonparametric sieve maximum likelihood approach. We
establish the asymptotic properties of the proposed estimator, and illustrate
its finite-sample properties using a simulation study. The application of our
method is illustrated using data from a cancer clinical study. An open-source R
package to implement the proposed method is available on CRAN.
| arxiv topic:stat.ME |
arxiv_dataset-98751806.0186 | Composite Weyl semimetal as a parent state for three dimensional
topologically ordered phases
cond-mat.str-el cond-mat.mes-hall
We introduce (3+1) dimensional models of short-range-interacting electrons
that form a strongly correlated many-body state whose low-energy excitations
are relativistic neutral fermions coupled to an emergent gauge field,
$\text{QED}_{4}$. We discuss the properties of this critical state and its
instabilities towards exotic phases such as a gapless `composite' Weyl
semimetal and fully gapped topologically ordered phases that feature anyonic
point-like as well as line-like excitations. These fractionalized phases
describe electronic insulators. They may be further enriched by symmetries
which results in the formation of non-trivial surface states.
| arxiv topic:cond-mat.str-el cond-mat.mes-hall |
arxiv_dataset-98761806.0196 | Pressure-induced Frustration of Magnetic Coupling in Elemental Europium
cond-mat.str-el
Applying linear response and the magnetic force theorem in correlated density
functional theory, the inter-sublattice exchange constants of antiferromagnetic
Eu are calculated and found to vanish near the pressure of P$_c$=82 GPa, just
where magnetic order is observed experimentally to be lost. The Eu $4f^7$
moment remains unchanged at high pressure, again in agreement with
spectroscopic measurements, leaving the picture of perfect frustration of
interatomic Ruderman-Kittel-Kasuya-Yoshida couplings in a broad metallic
background, leaving a state of electrons strongly exchange coupled to
arbitrarily oriented, possibly quasistatic local moments. This strongly
frustrated state gives way to superconductivity at T$_c$=1.7K, observed
experimentally. These phenomena, and free energy considerations related to
correlations, suggest an unusual phase of matter that is discussed within the
scenarios of the Doniach Kondo lattice phase diagram, the metallic spin glass
class, and itinerant spin liquid or spin gas systems.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-98771806.0206 | Effective definability of Kolchin polynomials
math.AC
While the natural model-theoretic ranks available in differentially closed
fields (of characteristic zero), namely Lascar and Morley rank, are known not
to be definable in families of differential varieties; in this note we show
that the differential-algebraic rank given by the Kolchin polynomial is in fact
definable. As a byproduct, we are able to prove that the property of being
weakly irreducible for a differential variety is also definable in families.
The question of full irreducibility remains open, it is known to be equivalent
to the generalized Ritt problem.
| arxiv topic:math.AC |
arxiv_dataset-98781806.0216 | Deep Bayesian regression models
stat.ME
Regression models are used for inference and prediction in a wide range of
applications providing a powerful scientific tool for researchers and analysts
from different fields. In many research fields the amount of available data as
well as the number of potential explanatory variables is rapidly increasing.
Variable selection and model averaging have become extremely important tools
for improving inference and prediction. However, often linear models are not
sufficient and the complex relationship between input variables and a response
is better described by introducing non-linearities and complex functional
interactions. Deep learning models have been extremely successful in terms of
prediction although they are often difficult to specify and potentially suffer
from overfitting. The aim of this paper is to bring the ideas of deep learning
into a statistical framework which yields more parsimonious models and allows
to quantify model uncertainty. To this end we introduce the class of deep
Bayesian regression models (DBRM) consisting of a generalized linear model
combined with a comprehensive non-linear feature space, where non-linear
features are generated just like in deep learning but combined with variable
selection in order to include only important features. DBRM can easily be
extended to include latent Gaussian variables to model complex correlation
structures between observations, which seems to be not easily possible with
existing deep learning approaches. Two different algorithms based on MCMC are
introduced to fit DBRM and to perform Bayesian inference. The predictive
performance of these algorithms is compared with a large number of state of the
art algorithms. Furthermore we illustrate how DBRM can be used for model
inference in various applications.
| arxiv topic:stat.ME |
arxiv_dataset-98791806.0226 | Dual-Mode Operation of an Optical Lattice Clock Using Strontium and
Ytterbium Atoms
physics.atom-ph
We have developed an optical lattice clock that can operate in dual modes: a
strontium (Sr) clock mode and an ytterbium (Yb) clock mode. Dual-mode operation
of the Sr-Yb optical lattice clock is achieved by alternately cooling and
trapping $^{87}$Sr and $^{171}$Yb atoms inside the vacuum chamber of the clock.
Optical lattices for Sr and Yb atoms were arranged with horizontal and vertical
configurations, respectively, resulting in a small distance of the order of 100
$\mu$m between the trapped Sr and Yb atoms. The $^{1}$S$_{0}$-$^{3}$P$_{0}$
clock transitions in the trapped atoms were interrogated in turn and the clock
lasers were stabilized to the transitions. We demonstrated the frequency ratio
measurement of the Sr and Yb clock transitions by using the dual-mode operation
of the Sr-Yb optical lattice clock. The dual-mode operation can reduce the
uncertainty of the blackbody radiation shift in the frequency ratio
measurement, because both Sr and Yb atoms share the same blackbody radiation.
| arxiv topic:physics.atom-ph |
arxiv_dataset-98801806.0236 | Effective virtual and residual properties of some arithmetic hyperbolic
3-manifolds
math.GT math.GR
We give an effective upper bound, for certain arithmetic hyperbolic
3-manifold groups obtained from a quadratic form construction, on the minimal
index of a subgroup that embeds in a fixed 6-dimensional right-angled
reflection group, stabilizing a totally geodesic subspace. In particular, for
manifold groups in any fixed commensurability class we show that the index of
such a subgroup is asymptotically smaller than any fractional power of the
volume of the manifold. We also give effective bounds on the geodesic residual
finiteness growths of closed hyperbolic manifolds that totally geodesically
immerse in non-compact right-angled reflection orbifolds, extending work of the
third author from the compact case. The first result gives examples to which
the second applies, and for these we give explicit bounds on geodesic residual
finiteness growth.
| arxiv topic:math.GT math.GR |
arxiv_dataset-98811806.0246 | The effect of the choice of neural network depth and breadth on the size
of its hypothesis space
cs.LG stat.ML
We show that the number of unique function mappings in a neural network
hypothesis space is inversely proportional to $\prod_lU_l!$, where $U_{l}$ is
the number of neurons in the hidden layer $l$.
| arxiv topic:cs.LG stat.ML |
arxiv_dataset-98821806.0256 | Automaticity of the sequence of the last nonzero digits of $n!$ in a
fixed base
math.NT
In 2011 Deshouillers and Ruzsa tried to argument that the sequence of the
last nonzero digit of $n!$ in base 12 is not automatic. This statement was
proved few years later by Deshoulliers. In this paper we provide alternate
proof that lets us generalize the problem and give an exact characterization in
which bases the sequence of the last nonzero digits of $n!$ is automatic.
| arxiv topic:math.NT |
arxiv_dataset-98831806.0266 | Analyzing Traffic Delay at Unmanaged Intersections
cs.MA
At an unmanaged intersection, it is important to understand how much traffic
delay may be caused as a result of microscopic vehicle interactions.
Conventional traffic simulations that explicitly track these interactions are
time-consuming. Prior work introduced an analytical traffic model for unmanaged
intersections. The traffic delay at the intersection is modeled as an
event-driven stochastic process, whose dynamics encode microscopic vehicle
interactions. This paper studies the traffic delay in a two-lane intersection
using the model. We perform rigorous analyses concerning the distribution of
traffic delay under different scenarios. We then discuss the relationships
between traffic delay and multiple factors such as traffic flow density,
unevenness of traffic flows, temporal gaps between two consecutive vehicles,
and the passing order.
| arxiv topic:cs.MA |
arxiv_dataset-98841806.0276 | Quasiconformal features and Fredholm eigenvalues of convex polygons
math.CV
An important open problem in geometric complex analysis is to find algorithms
for explicit determination of basic functionals intrinsically connected with
conformal and quasiconformal maps, such as their Teichmuller and Grunsky norms,
Fredholm eigenvalues and the quasireflection coefficient. This has not been
solved even for convex polygons. This case has intrinsic interest in view of
the connection of such polygons with the geometry of the universal Teichmuller
space.
We provide a new approach, based on affine transformations of univalent
functions.
| arxiv topic:math.CV |
arxiv_dataset-98851806.0286 | Ideals in Rings and Intermediate Rings of Measurable Functions
math.FA math.AC math.GN
The set of all maximal ideals of the ring $\mathcal{M}(X,\mathcal{A})$ of
real valued measurable functions on a measurable space $(X,\mathcal{A})$
equipped with the hull-kernel topology is shown to be homeomorphic to the set
$\hat{X}$ of all ultrafilters of measurable sets on $X$ with the
Stone-topology. This yields a complete description of the maximal ideals of
$\mathcal{M}(X,\mathcal{A})$ in terms of the points of $\hat{X}$. It is further
shown that the structure spaces of all the intermediate subrings of
$\mathcal{M}(X,\mathcal{A})$ containing the bounded measurable functions are
one and the same and are compact Hausdorff zero-dimensional spaces. It is
observed that when $X$ is a $P$-space, then $C(X) = \mathcal{M}(X,\mathcal{A})$
where $\mathcal{A}$ is the $\sigma$-algebra consisting of the zero-sets of $X$.
| arxiv topic:math.FA math.AC math.GN |
arxiv_dataset-98861806.0296 | Representation Learning of Entities and Documents from Knowledge Base
Descriptions
cs.CL cs.NE
In this paper, we describe TextEnt, a neural network model that learns
distributed representations of entities and documents directly from a knowledge
base (KB). Given a document in a KB consisting of words and entity annotations,
we train our model to predict the entity that the document describes and map
the document and its target entity close to each other in a continuous vector
space. Our model is trained using a large number of documents extracted from
Wikipedia. The performance of the proposed model is evaluated using two tasks,
namely fine-grained entity typing and multiclass text classification. The
results demonstrate that our model achieves state-of-the-art performance on
both tasks. The code and the trained representations are made available online
for further academic research.
| arxiv topic:cs.CL cs.NE |
arxiv_dataset-98871806.0306 | 2K(2\nu)-Capture in Xe-124: Results of Data Processing for an Exposure
of 37.7 kg x day
nucl-ex physics.ins-det
The results of the experimental search for two-neutrino $2K$-capture in
$^{124}$Xe with a large copper proportional counter obtained by processing the
data for an exposure of 37.7 kg$\times$day are presented. The experimental
setup is located at the Underground Low-Background Laboratory of the Baksan
Neutrino Observatory at a depth of 4900 m w.e. The combination of methods of
selection of useful signals with a unique set of characteristics and the event
topology taken into account allowed us to suppress the background in the energy
region of interest. A new half-life limit for $2K(2\nu)$-capture in $^{124}$Xe
was determined: T$_{1/2}\geq7.7\cdot10^{21}$ yrs (90\%
C.L.).
| arxiv topic:nucl-ex physics.ins-det |
arxiv_dataset-98881806.0316 | Reducing Metadata Leakage from Encrypted Files and Communication with
PURBs
cs.CR
Most encrypted data formats leak metadata via their plaintext headers, such
as format version, encryption schemes used, number of recipients who can
decrypt the data, and even the recipients' identities. This leakage can pose
security and privacy risks to users, e.g., by revealing the full membership of
a group of collaborators from a single encrypted e-mail, or by enabling an
eavesdropper to fingerprint the precise encryption software version and
configuration the sender used. We propose that future encrypted data formats
improve security and privacy hygiene by producing $\textit{Padded Uniform
Random Blobs}$ or PURBs: ciphertexts indistinguishable from random bit strings
to anyone without a decryption key. A PURB's content leaks $\textit{nothing at
all}$, even the application that created it, and is padded such that even its
length leaks as little as possible. Encoding and decoding ciphertexts with
$\textit{no}$ cleartext markers presents efficiency challenges, however. We
present cryptographically agile encodings enabling legitimate recipients to
decrypt a PURB efficiently, even when encrypted for any number of recipients'
public keys and/or passwords, and when these public keys are from different
cryptographic suites. PURBs employ Padm\'e, a~novel padding scheme that limits
information leakage via ciphertexts of maximum length $M$ to a practical
optimum of $O(\log \log M)$ bits, comparable to padding to a power of two, but
with lower overhead of at most $12\%$ and decreasing with larger payloads.
| arxiv topic:cs.CR |
arxiv_dataset-98891806.0326 | DBBRBF- Convalesce optimization for software defect prediction problem
using hybrid distribution base balance instance selection and radial basis
Function classifier
cs.SE
Software is becoming an indigenous part of human life with the rapid
development of software engineering, demands the software to be most reliable.
The reliability check can be done by efficient software testing methods using
historical software prediction data for development of a quality software
system. Machine Learning plays a vital role in optimizing the prediction of
defect-prone modules in real life software for its effectiveness. The software
defect prediction data has class imbalance problem with a low ratio of
defective class to non-defective class, urges an efficient machine learning
classification technique which otherwise degrades the performance of the
classification. To alleviate this problem, this paper introduces a novel hybrid
instance-based classification by combining distribution base balance based
instance selection and radial basis function neural network classifier model
(DBBRBF) to obtain the best prediction in comparison to the existing research.
Class imbalanced data sets of NASA, Promise and Softlab were used for the
experimental analysis. The experimental results in terms of Accuracy,
F-measure, AUC, Recall, Precision, and Balance show the effectiveness of the
proposed approach. Finally, Statistical significance tests are carried out to
understand the suitability of the proposed model.
| arxiv topic:cs.SE |
arxiv_dataset-98901806.0336 | Band gap and band offset of Ga$_2$O$_3$ and (Al$_x$Ga$_{1-x}$)$_2$O$_3$
alloys
cond-mat.mtrl-sci
Ga$_2$O$_3$ and (Al$_x$Ga$_{1-x}$)$_2$O$_3$ alloys are promising materials
for solar-blind UV photodetectors and high-power transistors. Basic key
parameters in the device design, such as band gap variation with alloy
composition and band offset between Ga$_2$O$_3$ and
(Al$_x$Ga$_{1-x}$)$_2$O$_3$, are yet to be established. Using density
functional theory with the HSE hybrid functional, we compute formation
enthalpies, band gaps, and band edge positions of (Al$_x$Ga$_{1-x}$)$_2$O$_3$
alloys in the monoclinic ($\beta$) and corundum ($\alpha$) phases. We find the
formation enthlapies of (Al$_x$Ga$_{1-x}$)$_2$O$_3$ alloys are significantly
lower than of (In$_x$Ga$_{1-x}$)$_2$O$_3$, and that (Al$_x$Ga$_{1-x}$)$_2$O$_3$
with $x$=0.5 can be considered as an ordered compound AlGaO$_3$ in the
monoclinic phase, with Al occupying the octahedral sites and Ga occupying the
tetrahedral sites. The direct band gaps of the alloys range from 4.69 to 7.03
eV for $\beta$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$ and from 5.26 to 8.56 eV for
$\alpha$-(Al$_x$Ga$_{1-x}$)$_2$O$_3$. Most of the band offset of the
(Al$_x$Ga$_{1-x}$)$_2$O$_3$ alloy arises from the discontinuity in the
conduction band. Our results are used to explain the available experimental
data, and consequences for designing modulation-doped field effect transistors
(MODFETs) based on (Al$_x$Ga$_{1-x}$)$_2$O$_3$/Ga$_2$O$_3$ are discussed.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-98911806.0346 | The calculation of differential and total cross sections for $W^+ W^-
\gamma$ production process in proton-proton collisions at LHC energies
hep-ph
The vector bosons production at the Large Hadron Collider makes it possible
to investigate in detail the basic structure of electroweak interactions.
Besides the LHC with a good accuracy will be measure production of weak bosons
($pp \to W^+W^-$). The production of weak bosons with photon ($pp \to
W^+W^-\gamma$) provides an increasingly powerful handle at higher
center-of-mass energies. We present phenomenological results for $WW\gamma$
production in proton-proton interaction at the Large Hadron Collider. In this
paper, we calculate the total and differential cross sections. We consider the
dependence of differential cross section distributions on transverse momentum
and rapidity particles, which are produced in the final state ($W^+$ and
$W^-$). We consider several important distributions, which are included in the
search for new physics at the Large Hadron Collider. The results for transverse
momentum distributions, rapidity distributions and total cross section are
presented.
| arxiv topic:hep-ph |
arxiv_dataset-98921806.0356 | Semantic Correspondence: A Hierarchical Approach
cs.CV
Establishing semantic correspondence across images when the objects in the
images have undergone complex deformations remains a challenging task in the
field of computer vision. In this paper, we propose a hierarchical method to
tackle this problem by first semantically targeting the foreground objects to
localize the search space and then looking deeply into multiple levels of the
feature representation to search for point-level correspondence. In contrast to
existing approaches, which typically penalize large discrepancies, our approach
allows for significant displacements, with the aim to accommodate large
deformations of the objects in scene. Localizing the search space by
semantically matching object-level correspondence, our method robustly handles
large deformations of objects. Representing the target region by concatenated
hypercolumn features which take into account the hierarchical levels of the
surrounding context, helps to clear the ambiguity to further improve the
accuracy. By conducting multiple experiments across scenes with non-rigid
objects, we validate the proposed approach, and show that it outperforms the
state of the art methods for semantic correspondence establishment.
| arxiv topic:cs.CV |
arxiv_dataset-98931806.0366 | High Performance and Scalable AWG for Superconducting Quantum Computing
eess.SP quant-ph
Superconducting quantum computer is manufactured based on semiconductor
process which makes qubits integration possible. At the same time, this kind of
qubit exhibits high performance fidelity, de-coherence time, scalability and
requires a programmable arbitrary waveform generator (AWG). This paper presents
implementation of an AWG which composed of two gigabit samples per second
(GSPS) sampling rate, 16 bit vertical resolution digital to analog converters
(DACs). The AWG integrated with separate microwave devices onto a metal plate
for the scale-up consideration. A special waveform sequence output controller
is designed to realize seamless waveform switching and arbitrary waveform
generator. The jitter in multiple AWG channels is around 10ps, Integral
nonlinearity (INL) as well as differential nonlinearity (DNL) is about 2 LSB,
and the qubit performance of the de-coherence time (T2*) achieved 33% promotion
over that of a commercial 1 GSPS, 14 bit AWG.
| arxiv topic:eess.SP quant-ph |
arxiv_dataset-98941806.0376 | Effects of quark-matter symmetry energy on hadron-quark coexistence in
neutron-star matter
nucl-th
We examine the effects of the isovector-vector coupling and
hypercharge-vector coupling in quark matter on hadron-quark coexistence in
neutron-star matter. The relativistic mean field theory with the TM1 parameter
set and an extended TM1 parameter set are used to describe hadronic matter, and
the Nambu-Jona-Lasinio model with scalar, isoscalar-vector, isovector-vector
and hypercharge-vector couplings is used to describe deconfined quark matter.
The hadron-quark phase transition is constructed via the Gibbs conditions for
phase equilibrium. The isovector-vector and hypercharge-vector couplings in
quark matter enhance the symmetry energy and hypercharge symmetry energy in
neutron-star matter, while their effects are found to be suppressed at high
densities by the strange quarks. As a result, the hadron-quark mixed phase
shrinks with only isovector-vector coupling and moves to higher density with
isovector-vector and hypercharge-vector couplings. The maximum mass of
neutron-star increases slightly with isovector-vector and hypercharge-vector
couplings.
| arxiv topic:nucl-th |
arxiv_dataset-98951806.0386 | Air-Ground Integrated Vehicular Network Slicing with Content Pushing and
Caching
cs.NI cs.IT math.IT
In this paper, an Air-Ground Integrated VEhicular Network (AGIVEN)
architecture is proposed, where the aerial High Altitude Platforms (HAPs)
proactively push contents to vehicles through large-area broadcast while the
ground roadside units (RSUs) provide high-rate unicast services on demand. To
efficiently manage the multi-dimensional heterogeneous resources, a
service-oriented network slicing approach is introduced, where the AGIVEN is
virtually divided into multiple slices and each slice supports a specific
application with guaranteed quality of service (QoS). Specifically, the
fundamental problem of multi-resource provisioning in AGIVEN slicing is
investigated, by taking into account typical vehicular applications of
location-based map and popularity-based content services. For the
location-based map service, the capability of HAP-vehicle proactive pushing is
derived with respect to the HAP broadcast rate and vehicle cache size, wherein
a saddle point exists indicating the optimal communication-cache resource
trading. For the popular contents of common interests, the average on-board
content hit ratio is obtained, with HAPs pushing newly generated contents to
keep on-board cache fresh. Then, the minimal RSU transmission rate is derived
to meet the average delay requirements of each slice. The obtained analytical
results reveal the service-dependent resource provisioning and trading
relationships among RSU transmission rate, HAP broadcast rate, and vehicle
cache size, which provides guidelines for multi-resource network slicing in
practice. Simulation results demonstrate that the proposed AGIVEN network
slicing approach matches the multi-resources across slices, whereby the RSU
transmission rate can be saved by 40% while maintaining the same QoS.
| arxiv topic:cs.NI cs.IT math.IT |
arxiv_dataset-98961806.0396 | AGIL: Learning Attention from Human for Visuomotor Tasks
cs.CV cs.AI cs.LG
When intelligent agents learn visuomotor behaviors from human demonstrations,
they may benefit from knowing where the human is allocating visual attention,
which can be inferred from their gaze. A wealth of information regarding
intelligent decision making is conveyed by human gaze allocation; hence,
exploiting such information has the potential to improve the agents'
performance. With this motivation, we propose the AGIL (Attention Guided
Imitation Learning) framework. We collect high-quality human action and gaze
data while playing Atari games in a carefully controlled experimental setting.
Using these data, we first train a deep neural network that can predict human
gaze positions and visual attention with high accuracy (the gaze network) and
then train another network to predict human actions (the policy network).
Incorporating the learned attention model from the gaze network into the policy
network significantly improves the action prediction accuracy and task
performance.
| arxiv topic:cs.CV cs.AI cs.LG |
arxiv_dataset-98971806.0406 | Strange superconductivity near an antiferromagnetic heavy fermion
quantum critical point
cond-mat.supr-con
The heavy fermion CeMIn5 family with M = Co, Rh, Ir provide a prototypical
example of strange superconductors with unconventional d-wave pairing and
strange metal normal state, emerged near an antiferromagnetic quantum critical
point. The microscopic origin of strange superconductor and its link to
antiferromagnetic quantum criticality and strange metal state are still open
issues. We propose a microscopic mechanism for strange superconductor, based on
the coexistence and competition between the Kondo correlation and the quasi-2d
short-ranged antiferromagnetic resonating-valence-bond spin-liquid near the
antiferromagnetic quantum critical point via a large-N Kondo-Heisenberg model
and renormalization group analysis beyond the mean-field level. We find the
coexistence (competition) between the two types of correlations well explains
the overall features of superconducting and strange metal state. The interplay
of these two effects provides a qualitative understanding on how
superconductivity emerges from the SM state and the observed superconducting
phase diagrams for CeMIn5 near the anti-ferromagnetic quantum critical point.
| arxiv topic:cond-mat.supr-con |
arxiv_dataset-98981806.0416 | Evolved stars in the Local Group galaxies - II. AGB, RSG stars and dust
production in IC10
astro-ph.SR astro-ph.GA
We study the evolved stellar population of the Local Group galaxy IC10, with
the aim of characterizing the individual sources observed and to derive global
information on the galaxy, primarily the star formation history and the dust
production rate. To this aim, we use evolutionary sequences of low- and
intermediate-mass ($M < 8~M_{\odot}$) stars, evolved through the asymptotic
giant branch phase, with the inclusion of the description of dust formation. We
also use models of higher mass stars. From the analysis of the distribution of
stars in the observational planes obtained with IR bands, we find that the
reddening and distance of IC10 are $E(B-V)=1.85$ mag and $d=0.77$ Mpc,
respectively. The evolved stellar population is dominated by carbon stars, that
account for $40\%$ of the sources brighter than the tip of the red giant
branch. Most of these stars descend from $\sim 1.1-1.3~M_{\odot}$ progenitors,
formed during the major epoch of star formation, which occurred $\sim 2.5$ Gyr
ago. The presence of a significant number of bright stars indicates that IC10
has been site of significant star formation in recent epochs and currently
hosts a group of massive stars in the core helium-burning phase. Dust
production in this galaxy is largely dominated by carbon stars; the overall
dust production rate estimated is $7\times 10^{-6}~M_{\odot}$/yr.
| arxiv topic:astro-ph.SR astro-ph.GA |
arxiv_dataset-98991806.0426 | On the diameter and incidence energy of iterated total graphs
math.SP math.CO
The total graph of $G$, $\mathcal T(G)$ is the graph whose set of vertices is
the union of the sets of vertices and edges of $G$, where two vertices are
adjacent if and only if they stand for either incident or adjacent elements in
$G$. Let $\mathcal{T}^1(G)=\mathcal{T}(G)$, the total graph of $G$. For
$k\geq2$, the $k\text{-}th$ iterated total graph of $G$, $\mathcal{T}^k(G)$, is
defined recursively as $\mathcal{T}^k(G)=\mathcal{T}(\mathcal{T}^{k-1}(G)).$ If
$G$ is a connected graph its diameter is the maximum distance between any pair
of vertices in $G$. The incidence energy $IE(G)$ of $G$ is the sum of the
singular values of the incidence matrix of $G$. In this paper for a given
integer $k$ we establish a necessary and sufficient condition under which
$diam(\mathcal{T}^{r+1}(G))>k-r,$ $r\geq0$. In addition, bounds for the
incidence energy of the iterated graph $\mathcal{T}^{r+1}(G)$ are obtained,
provided $G$ to be a regular graph. Finally, new families of non-isomorphic
cospectral graphs are exhibited.
| arxiv topic:math.SP math.CO |
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