text
stringlengths 66
4.65k
|
|---|
English: Neutron resonance spectrometry (NRS) has been used to measure the temperature
inside Mo samples during shock loading. The temperatures obtained were
significantly higher than predicted assuming ideal hydrodynamic loading. The
effect of plastic flow and non-ideal projectile behavior were assessed. Plastic
flow was calculated self-consistently with the shock jump conditions: this is
necessary for a rigorous estimate of the locus of shock states accessible.
Plastic flow was estimated to contribute a temperature rise of 53K compared
with hydrodynamic flow. Simulations were performed of the operation of the
explosively-driven projectile system used to induce the shock in the Mo sample.
The simulations predicted that the projectile was significantly curved on
impact, and still accelerating. The resulting spatial variations in load,
including radial components of velocity, were predicted to increase the
apparent temperature that would be deduced from the width of the neutron
resonance by 160K. These corrections are sufficient to reconcile the apparent
temperatures deduced using NRS with the accepted properties of Mo, in
particular its equation of state.
Chinese: 中子共振光谱学（NRS）已被用于测量在冲击加载过程中Mo样品内部的温度。所获得的温度显著高于假设理想流体动力学加载时的预测。评估了塑性流动和非理想弹丸行为的影响。塑性流动与冲击跳跃条件自洽地进行了计算：这对于严格估计可访问的冲击状态轨迹是必要的。与流体动力学流动相比，塑性流动估计贡献了53K的温度升高。对用于在Mo样品中诱导冲击的爆炸驱动弹丸系统的操作进行了模拟。模拟预测弹丸在撞击时显著弯曲，并且仍在加速。预测到的载荷的空间变化，包括速度的径向分量，预计将使从中子共振宽度中推导出的表观温度增加160K。这些修正足以使使用NRS推导出的表观温度与Mo的公认特性相协调，特别是其状态方程。
|
English: Dynamic decision-making under distributional shifts is of fundamental
interest in theory and applications of reinforcement learning: The distribution
of the environment in which the data is collected can differ from that of the
environment in which the model is deployed. This paper presents two novel
model-free algorithms, namely the distributionally robust Q-learning and its
variance-reduced counterpart, that can effectively learn a robust policy
despite distributional shifts. These algorithms are designed to efficiently
approximate the $q$-function of an infinite-horizon $\gamma$-discounted robust
Markov decision process with Kullback-Leibler ambiguity set to an entry-wise
$\epsilon$-degree of precision. Further, the variance-reduced distributionally
robust Q-learning combines the synchronous Q-learning with variance-reduction
techniques to enhance its performance. Consequently, we establish that it
attains a minimax sample complexity upper bound of $\tilde
O(|\mathbf{S}||\mathbf{A}|(1-\gamma)^{-4}\epsilon^{-2})$, where $\mathbf{S}$
and $\mathbf{A}$ denote the state and action spaces. This is the first
complexity result that is independent of the ambiguity size $\delta$, thereby
providing new complexity theoretic insights. Additionally, a series of
numerical experiments confirm the theoretical findings and the efficiency of
the algorithms in handling distributional shifts.
Chinese: 在强化学习理论和应用中，当数据收集环境与模型部署环境的分布不同时，动态决策制定是一个基础性的问题：数据收集环境中的分布可能与模型部署环境中的分布不同。本文提出了两个新颖的模型无关算法，即分布稳健的Q学习和其方差减少的变体，它们可以在分布变化的情况下有效地学习稳健策略。这些算法旨在高效地近似无限时限$\gamma$折扣稳健马尔可夫决策过程的$q$函数，其中Kullback-Leibler不确定性集被限制为每个元素的$\epsilon$度精度。此外，方差减少的分布稳健Q学习结合了同步Q学习和方差减少技术以提升其性能。因此，我们证明了它达到一个$\tilde O(|\mathbf{S}||\mathbf{A}|(1-\gamma)^{-4}\epsilon^{-2})$的最小化样本复杂度上界，其中$\mathbf{S}$和$\mathbf{A}$分别表示状态和动作空间。这是第一个独立于不确定性大小$\delta$的复杂度结果，从而提供了新的复杂性理论见解。此外，一系列数值实验证实了理论发现以及算法在处理分布变化时的效率。
|
English: We present pulse phase resolved spectra of the hypergiant high mass X-ray
binary GX 301-2. We observed the source in 2001 October with RXTE continuously
for a total on-source time of almost 200ksec. We model the continuum with both,
a heavily absorbed partial covering model and a reflection model. In either
case we find that the well known cyclotron resonant scattering feature (CRSF)
at 35keV is - although present at all pulse phases - strongly variable over the
pulse: the line position varies by 25% from 30keV in the fall of the secondary
pulse to 38keV in the fall of the main pulse where it is deepest. The line
variability implies that we are seeing regions of magnetic field strength
varying between 3.4 10^12G and 4.2 10^12G.
Chinese: 我们展示了超巨星高质量X射线双星GX 301-2的脉冲相位分辨谱。我们在2001年10月使用RXTE连续观测该源，总曝光时间接近200k秒。我们用部分覆盖模型和反射模型来拟合连续谱。无论哪种情况，我们都发现众所周知的35keV的磁共振散射特征（CRSF）在所有脉冲相位上均存在，但脉冲相位间变化显著：从次脉冲下降时的30keV到主脉冲下降时的38keV，变化幅度达25%，此时CRSF最深。CRSF的变化表明我们观察到磁场强度在3.4×10^12G到4.2×10^12G之间变化的地区。
|
English: We study the microwave absorption of a driven three-level quantum system,
which is realized by a superconducting flux quantum circuit (SFQC), with a
magnetic driving field applied to the two upper levels. The interaction between
the three-level system and its environment is studied within the Born-Markov
approximation, and we take into account the effects of the driving field on the
damping rates of the three-level system. We study the linear response of the
driven three-level SFQC to a weak probe field. The linear magnetic
susceptibility of the SFQC can be changed by both the driving field and the
bias magnetic flux. When the bias magnetic flux is at the optimal point, the
transition from the ground state to the second excited state is forbidden and
the three-level SFQC has a ladder-type transition. Thus, the SFQC responds to
the probe field like natural atoms with ladder-type transitions. However, when
the bias magnetic flux deviates from the optimal point, the three-level SFQC
has a cyclic transition, thus it responds to the probe field like a combination
of natural atoms with ladder-type transitions and natural atoms with
$\Lambda$-type transitions. In particular, we provide detailed discussions on
the conditions for realizing electromagnetically induced transparency and
Autler-Townes splitting in three-level SFQCs.
Chinese: 我们研究了一个由超导通量量子电路（SFQC）实现的驱动三能级量子系统的微波吸收情况，该系统通过施加于两个上能级的磁场驱动场来实现。在Born-Markov近似下研究了三能级系统与其环境的相互作用，并考虑了驱动场对三能级系统阻尼率的影响。我们研究了驱动三能级SFQC对弱探测场的线性响应。SFQC的线性磁化率可以通过驱动场和偏置磁通量来改变。当偏置磁通量处于最佳点时，从基态到第二激发态的跃迁被禁止，三能级SFQC具有梯形跃迁。因此，SFQC对探测场的响应类似于具有梯形跃迁的自然原子。然而，当偏置磁通量偏离最佳点时，三能级SFQC具有循环跃迁，因此它对探测场的响应类似于具有梯形跃迁和$\Lambda$型跃迁的自然原子的组合。特别是，我们详细讨论了实现三能级SFQC中电磁诱导透明度和Autler-Townes分裂的条件。
|
English: Objective: We propose a novel approach for modelling the inter-dependence of
electrical and mechanical phenomena in nervous cells, by using electro-thermal
equivalences in finite element (FE) analysis so that existing thermo-mechanical
tools can be applied. Methods: First, the equivalence between electrical and
thermal properties of the nerve materials is established, and results of a pure
heat conduction analysis performed in Abaqus CAE Software 6.13-3 are validated
with analytical solutions for a range of steady and transient conditions. This
validation includes the definition of equivalent active membrane properties
that enable prediction of the action potential. Then, as a step towards fully
coupled models, electromechanical coupling is implemented through the
definition of equivalent piezoelectric properties of the nerve membrane using
the thermal expansion coefficient, enabling prediction of the mechanical
response of the nerve to the action potential. Results: Results of the coupled
electro-mechanical model are validated with previously published experimental
results of deformation for the squid giant axon, crab nerve fibre and garfish
olfactory nerve fibre. Conclusion: A simplified coupled electro-mechanical
modelling approach is established through an electro-thermal equivalent FE
model of a nervous cell for biomedical applications. Significance: One of the
key findings is the mechanical characterization of the neural activity in a
coupled electro-mechanical domain, which provides insights into the
electromechanical behaviour of nervous cells, such as thinning of the membrane.
This is a first step towards modelling 3D electromechanical alteration induced
by trauma at nerve bundle, tissue and organ levels.
Chinese: 目标：我们提出了一种新的方法，通过在有限元（FE）分析中使用电热等效，来模拟神经细胞中电和机械现象的相互依赖性，使得现有的热力学机械工具可以应用。方法：首先，建立了神经材料电学和热学性质之间的等价关系，并在Abaqus CAE软件6.13-3中进行了纯热传导分析，与不同稳态和瞬态条件下的解析解进行了验证。这一验证包括定义等效的活性膜属性，从而可以预测动作电位。然后，为了实现完全耦合的模型，通过定义使用热膨胀系数等效的神经膜的压电性质，实现了电机械耦合，从而可以预测神经对动作电位的机械响应。结果：耦合的电机械模型的结果与先前发表的关于章鱼巨轴突、螃蟹神经纤维和鲶鱼嗅觉神经纤维形变的实验结果进行了验证。结论：通过电热等效的有限元模型，为生物医学应用建立了一个简化的耦合电机械建模方法。重要性：一个关键发现是在耦合电机械域中对神经活动进行机械表征，这为神经细胞的电机械行为，如膜的变薄，提供了见解。这是在神经束、组织和器官水平上模拟由创伤引起的3D电机械变化迈出的第一步。
|
English: Single photon spectra in heavy-ion collisions at SPS energies are studied in
the relativistic transport model that incorporates self-consistently the change
of hadron masses in dense matter. We separate the total photon spectrum into
`background' arising from the radiative decays of $\pi^0$ and $\eta$ mesons,
and the `themal' one from other sources. For the latter we include
contributions from radiative decays of $\rho$, $\omega$, $\eta'$, and $a_1$,
radiative decays of baryon resonances, as well as two-body processes such as
$\pi\pi \to \rho\gamma$ and $\pi\rho \to \pi\gamma$. It is found that more than
95% of all photons come from the decays of $\pi^0$ and $\eta$ mesons, while the
thermal photons account for less than 5% of the total photon yield. The thermal
photon spectra in our calculations with either free or in-medium meson masses
do not exceed the upper bound set by the experimental measurment of the WA80
Collaboration.
Chinese: 在SPS能量下，重离子碰撞中的单光子谱在相对论传输模型中被研究，该模型自洽地包含了在致密物质中重子质量的改变。我们将总光子谱分为由$\pi^0$和$\eta$介子的辐射衰变产生的“背景”光子，以及来自其他来源的“热”光子。对于后者，我们包括了$\rho$、$\omega$、$\eta'$和$a_1$的辐射衰变、重子共振的辐射衰变，以及$\pi\pi \to \rho\gamma$和$\pi\rho \to \pi\gamma$等双体过程的贡献。研究发现，超过95%的所有光子都来自$\pi^0$和$\eta$介子的衰变，而热光子占总光子产量的比例不到5%。在我们使用自由或介质中介子质量进行的计算中，热光子谱没有超过WA80合作组实验测量的上限。
|
English: The identification of magnetic quantum critical points in heavy fermion
metals has provided an ideal setting for experimentally studying quantum
criticality. Motivated by these experiments, considerable theoretical efforts
have recently been devoted to reexamine the interplay between Kondo screening
and magnetic interactions in Kondo lattice systems. A local quantum critical
picture has emerged, in which magnetic interactions suppress Kondo screening
precisely at the magnetic quantum critical point (QCP). The Fermi surface
undergoes a large reconstruction across the QCP and the coherence scale of the
Kondo lattice vanishes at the QCP. The dynamical spin susceptibility exhibits
$\omega/T$ scaling and non-trivial exponents describe the temperature and
frequency dependence of various physical quantities. These properties are to be
contrasted with the conventional spin-density-wave (SDW) picture, in which the
Kondo screening is not suppressed at the QCP and the Fermi surface evolves
smoothly across the phase transition. In this article we discuss recent
microscopic studies of Kondo lattices within an extended dynamical mean field
theory (EDMFT). We summarize the earlier work based on an analytical
$\epsilon$-expansion renormalization group method, and expand on the more
recent numerical results. We also discuss the issues that have been raised
concerning the magnetic phase diagram. We show that the zero-temperature
magnetic transition is second order when double counting of the RKKY
interactions is avoided in EDMFT.
Chinese: 在重费米子金属中识别磁量子临界点为实验研究量子临界性提供了一个理想的背景。受这些实验的启发，最近有相当多的理论研究致力于重新审视康多晶格系统中康多屏蔽和磁相互作用的相互作用。一个局部量子临界图像已经出现，其中磁相互作用恰好抑制了康多屏蔽，发生在磁量子临界点（QCP）。费米面在QCP处经历了一次大的重构，康多晶格的相干尺度在QCP处消失。动态自旋磁化率表现出$\omega/T$标度，非平凡的指数描述了各种物理量的温度和频率依赖性。这些性质需要与传统的自旋密度波（SDW）图像进行对比，在传统的SDW图像中，康多屏蔽在QCP处没有被抑制，费米面在相变过程中平滑演变。在本文中，我们讨论了在扩展动态平均场理论（EDMFT）框架下对康多晶格的最近微观研究。我们总结了基于解析$\epsilon$-展开重整化群方法的早期工作，并扩展了最近的一些数值结果。我们还讨论了有关磁相图提出的问题。我们表明，在EDMFT中避免RKKY相互作用的重复计数时，零温度磁转变是二阶的。
|
English: In the past year several constructions of non-invertible symmetries in
Quantum Field Theory in $d\geq 3$ have appeared. In this paper we provide a
unified perspective on these constructions. Central to this framework are
so-called theta defects, which generalize the notion of theta-angles, and allow
the construction of universal and non-universal topological symmetry defects.
We complement this physical analysis by proposing a mathematical framework
(based on higher-fusion categories) that converts the physical construction of
non-invertible symmetries into a concrete computational scheme.
Chinese: 在过去一年中，在$d\geq 3$维量子场论中出现了若干非可逆对称的构造。本文对这些构造提供了一个统一的视角。这一框架的核心是所谓的θ缺陷，它推广了θ角的概念，并允许构造通用和非通用的拓扑对称缺陷。我们通过提出一个基于高融合范畴的数学框架来补充这一物理分析，该框架将非可逆对称的物理构造转化为具体的计算方案。
|
English: his paper presents two novel approaches to solving the classic board game
mastermind, including a variant of simulated annealing (SA) and a technique we
term maximum expected reduction in consistency (MERC). In addition, we compare
search results for these algorithms to two baseline search methods: a random,
uninformed search and the method of minimizing maximum query partition sets as
originally developed by both Donald Knuth and Peter Norvig.
Chinese: 他的论文提出了两种解决经典棋盘游戏Mastermind的新方法，包括模拟退火（SA）的一种变体以及我们称之为最大预期一致性减少（MERC）的技术。此外，我们还比较了这些算法的搜索结果与两种基线搜索方法：一种随机、无信息的搜索以及由Donald Knuth和Peter Norvig最初开发的最小化最大查询分区集的方法。
|
English: In the modern world, technology is at its peak. Different avenues in
programming and technology have been explored for data analysis, automation,
and robotics. Machine learning is key to optimize data analysis, make accurate
predictions, and hasten/improve existing functions. Thus, presently, the field
of machine learning in artificial intelligence is being developed and its uses
in varying fields are being explored. One field in which its uses stand out is
that of microbial biosynthesis. In this paper, a comprehensive overview of the
differing machine learning programs used in biosynthesis is provided, alongside
brief descriptions of the fields of machine learning and microbial biosynthesis
separately. This information includes past trends, modern developments, future
improvements, explanations of processes, and current problems they face. Thus,
this paper's main contribution is to distill developments in, and provide a
holistic explanation of, 2 key fields and their applicability to improve
industry/research. It also highlights challenges and research directions,
acting to instigate more research and development in the growing fields.
Finally, the paper aims to act as a reference for academics performing
research, industry professionals improving their processes, and students
looking to understand the concept of machine learning in biosynthesis.
Chinese: 在现代世界中，技术达到了顶峰。在编程和技术领域探索了不同的途径以进行数据分析、自动化和机器人技术。机器学习是优化数据分析、做出准确预测和加快/改进现有功能的关键。因此，目前人工智能领域的机器学习正在得到发展，其在不同领域的应用也在被探索。其中，微生物生物合成是其应用突出的一个领域。在这篇论文中，提供了用于生物合成的不同机器学习程序的全面概述，以及机器学习领域和微生物生物合成领域的简要描述。这些信息包括过去趋势、现代发展、未来改进、过程解释和当前面临的问题。因此，这篇论文的主要贡献是对两个关键领域的发展进行提炼，并提供对其在改善行业/研究中的应用的整体解释。它还突出了挑战和研究方向，旨在激发更多在新兴领域的研发活动。最后，这篇论文旨在作为学术研究人员、改进其流程的行业专业人士和希望理解生物合成中机器学习概念的学生的参考。
|
English: A reversible handle on graphene carrier density, other than the gate electric
field, is desirable for memory applications of graphene. Our experiments show
that the commonly observed carrier density hysteresis in graphene on SiO$_2$
due to interface water/oxygen vanishes at temperatures below 250 K. The state
of these species, which affects the graphene carrier density, at low
temperatures can be reversibly controlled by thermal cycling to room
temperature at different gate voltages. Further, devices prepared with
relatively dry interface, and thus showing negligible hysteresis at room
temperature, show a marked increase in hysteresis on heating above room
temperature. Thus thermal-cycling, to high temperatures and under gate-voltage,
provides a reversible handle on carrier density. These results are discussed in
terms of temperature and interface-water density dependence of redox-reaction
kinetics.
Chinese: 对于石墨烯的存储应用，除了栅极电场外，还希望对石墨烯载流子密度有一个可逆的控制。我们的实验表明，由于界面水/氧的存在，在SiO$_2$上观察到的石墨烯载流子密度滞后现象在低于250 K的温度下消失。这些物种的状态，它影响石墨烯载流子密度，在低温下可以通过在不同的栅极电压下进行热循环至室温来可逆控制。此外，使用相对干燥的界面制备的器件，在室温下表现出可忽略的滞后现象，在加热至室温以上时，滞后现象显著增加。因此，在高温和栅极电压下进行热循环，为载流子密度提供了一个可逆的控制手段。这些结果是用温度和界面水密度对氧化还原反应动力学依赖性的术语来讨论的。
|
English: In this work a method for generating a long-range optical pulling force is
presented which is realized by utilizing a vortex beam and a device designed
based on transformation optics through conformal mapping. The device works by
transforming an input perfect vortex beam into an almost non-paraxial plane
wave, and generates a pulling force by maximizing the forward momentum of the
beam. A three-dimensional full-wave analysis of the device is performed and the
optical force is computed by the Maxwell stress tensor method. The simulation
results show a very good agreement with the theoretical calculations.
Chinese: 在这项工作中，提出了一种生成长程光学牵引力的方法，该方法通过利用涡旋光束和基于变换光学并通过共形映射设计的装置来实现。该装置通过将输入的完美涡旋光束转换成几乎非傍轴平面波来工作，并通过最大化光束的前进动量来产生牵引力。对装置进行了三维全波分析，并使用麦克斯韦应力张量法计算了光学力。仿真结果与理论计算吻合得非常好。
|
English: The term Stone-type duality often refers to a dual equivalence between a
category of lattices or other partially ordered structures on one side and a
category of topological structures on the other. This paper is part of a larger
endeavour that aims to extend a web of Stone-type dualities from ordered to
metric structures and, more generally, to quantale-enriched categories. In
particular, we improve our previous work and show how certain duality results
for categories of [0,1]-enriched Priestley spaces and [0,1]-enriched relations
can be restricted to functions. In a broader context, we investigate the
category of quantale-enriched Priestley spaces and continuous functors, with
emphasis on those properties which identify the algebraic nature of the dual of
this category.
Chinese: 术语“Stone型对偶”通常指的是一方面是格或其它部分有序结构的一个范畴，另一方面是拓扑结构的一个范畴之间的对偶等价。本文是更大一个努力的一部分，旨在将Stone型对偶的网络从有序结构扩展到度量结构，更一般地，扩展到量态丰富的范畴。特别是，我们改进了我们之前的工作，并展示了某些关于[0,1]丰富Priestley空间范畴和[0,1]丰富关系的对偶结果可以限制到函数上。在更广泛的环境中，我们研究了量态丰富的Priestley空间和连续函子的范畴，重点在于那些能够识别这个范畴对偶的代数性质的属性。
|
English: We investigate the estimation properties of the mixture of experts (MoE)
model in a high-dimensional setting, where the number of predictors is much
larger than the sample size, and for which the literature is particularly
lacking in theoretical results. We consider the class of softmax-gated Gaussian
MoE (SGMoE) models, defined as MoE models with softmax gating functions and
Gaussian experts, and focus on the theoretical properties of their
$l_1$-regularized estimation via the Lasso. To the best of our knowledge, we
are the first to investigate the $l_1$-regularization properties of SGMoE
models from a non-asymptotic perspective, under the mildest assumptions, namely
the boundedness of the parameter space. We provide a lower bound on the
regularization parameter of the Lasso penalty that ensures non-asymptotic
theoretical control of the Kullback--Leibler loss of the Lasso estimator for
SGMoE models. Finally, we carry out a simulation study to empirically validate
our theoretical findings.
Chinese: 我们研究在高维设置下混合专家（MoE）模型的估计性质，其中预测器的数量远大于样本量，而对于这一点，文献中缺乏理论结果。我们考虑软阈值高斯MoE（SGMoE）模型类，定义为具有softmax门控函数和高斯专家的MoE模型，并关注它们通过Lasso的$l_1$正则化估计的理论性质。据我们所知，我们是第一个从非渐近视角研究SGMoE模型的$l_1$正则化性质的人，在最温和的假设下，即参数空间的有界性。我们提供了一个Lasso惩罚正则化参数的下界，确保SGMoE模型Lasso估计器的Kullback-Leibler损失的渐近理论控制。最后，我们进行了一项模拟研究，以经验验证我们的理论发现。
|
English: A foundational requirement of a deployed ML model is to generalize to data
drawn from a testing distribution that is different from training. A popular
solution to this problem is to adapt a pre-trained model to novel domains using
only unlabeled data. In this paper, we focus on a challenging variant of this
problem, where access to the original source data is restricted. While fully
test-time adaptation (FTTA) and unsupervised domain adaptation (UDA) are
closely related, the advances in UDA are not readily applicable to TTA, since
most UDA methods require access to the source data. Hence, we propose a new
approach, CATTAn, that bridges UDA and FTTA, by relaxing the need to access
entire source data, through a novel deep subspace alignment strategy. With a
minimal overhead of storing the subspace basis set for the source data, CATTAn
enables unsupervised alignment between source and target data during
adaptation. Through extensive experimental evaluation on multiple 2D and 3D
vision benchmarks (ImageNet-C, Office-31, OfficeHome, DomainNet, PointDA-10)
and model architectures, we demonstrate significant gains in FTTA performance.
Furthermore, we make a number of crucial findings on the utility of the
alignment objective even with inherently robust models, pre-trained ViT
representations and under low sample availability in the target domain.
Chinese: 部署的机器学习模型的一个基本要求是能够泛化到与训练数据不同的测试分布数据。解决此问题的一个流行方案是仅使用无标签数据将预训练模型适配到新领域。在本文中，我们关注这一问题的具有挑战性的变体，即无法获取原始源数据。虽然全测试时适配（FTTA）和无监督领域适配（UDA）密切相关，但UDA的进展并不容易应用于TTA，因为大多数UDA方法需要访问源数据。因此，我们提出了一种新方法CATTAn，通过一种新颖的深度子空间对齐策略，连接UDA和FTTA，从而放宽了访问整个源数据的需要。通过存储源数据子空间基集的最小开销，CATTAn能够在适配过程中实现源数据和目标数据之间的无监督对齐。在多个2D和3D视觉基准（ImageNet-C、Office-31、OfficeHome、DomainNet、PointDA-10）以及模型架构上的大量实验评估表明，FTTA性能显著提升。此外，我们还对对齐目标在具有内在鲁棒性的模型、预训练ViT表征以及目标领域样本可用性低的情况下效用做出了若干关键发现。
|
English: In recent decades the world has experienced rates of urban growth
unparalleled in any other period of history and this growth is shaping the
environment in which an increasing proportion of us live. In this paper we use
a longitudinal dataset from Foursquare, a location-based social network, to
analyse urban growth across 100 major cities worldwide.
Initially we explore how urban growth differs in cities across the world. We
show that there exists a strong spatial correlation, with nearby pairs of
cities more likely to share similar growth profiles than remote pairs of
cities. Subsequently we investigate how growth varies inside cities and
demonstrate that, given the existing local density of places,
higher-than-expected growth is highly localised while lower-than-expected
growth is more diffuse. Finally we attempt to use the dataset to characterise
competition between new and existing venues. By defining a measure based on the
change in throughput of a venue before and after the opening of a new nearby
venue, we demonstrate which venue types have a positive effect on venues of the
same type and which have a negative effect. For example, our analysis confirms
the hypothesis that there is large degree of competition between bookstores, in
the sense that existing bookstores normally experience a notable drop in
footfall after a new bookstore opens nearby. Other place categories however,
such as Airport Gates or Museums, have a cooperative effect and their presence
fosters higher traffic volumes to nearby places of the same type.
Chinese: 在过去的几十年里，世界经历了历史上任何其他时期都无法比拟的城市增长率，这种增长正在塑造我们中越来越多的人居住的环境。在这篇论文中，我们使用来自Foursquare的纵向数据集，一个基于位置的社会网络，来分析全球100个主要城市的城市增长情况。
最初，我们探讨了全球不同城市之间城市增长的不同之处。我们发现存在强烈的空间相关性，相邻城市对之间共享相似增长特征的可能性比遥远城市对之间要高。随后，我们研究了城市内部的增长差异，并证明，考虑到现有地点的局部密度，高于预期的增长高度集中，而低于预期的增长则更为分散。最后，我们试图使用数据集来描述新旧场所之间的竞争。通过定义一个基于新近开业的相邻场所开业前后场所吞吐量变化的度量，我们展示了哪些场所类型对同类型的场所产生积极影响，哪些产生消极影响。例如，我们的分析证实了这样一个假设，即书店之间存在大量的竞争，因为在附近新开一家书店后，现有的书店通常会出现客流量明显下降的情况。然而，其他场所类别，如机场登机口或博物馆，则具有合作效应，它们的存在促进了同类型附近场所的交通量增加。
|
English: Classical dynamical systems close to a critical point are known to act as
efficient sensors due to a strongly nonlinear response. We explore such systems
in the quantum regime by modeling a quantum version of a driven van der Pol
oscillator. We find the classical response survives down to one excitation
quantum. At very weak drives, genuine quantum features arise, including
diverging and negative susceptibilities. Further, the linear response is
greatly enhanced by using a strong incoherent pump. These results are largely
generic and can be probed in current experimental platforms suited for quantum
sensing.
Chinese: 经典动力学系统在接近临界点时，由于其强烈的非线性响应，已知可以作为高效的传感器。我们通过模拟驱动van der Pol振子的量子版本，在量子域内探索此类系统。我们发现经典响应一直持续到单个激发量子。在非常微弱的驱动下，出现了真正的量子特征，包括发散和负介电常数。此外，通过使用强烈的非相干泵，线性响应得到了极大的增强。这些结果在很大程度上是通用的，可以在适用于量子传感的当前实验平台上进行探测。
|
English: For a class of negative slowly decaying potentials including the attractive
Coulombic one we study the classical scattering theory in the low-energy
regime. We construct a (continuous) family of classical orbits parametrized by
initial position $x\in \R^d$, final direction $\omega\in S^{d-1}$ of escape (to
infinity) and the energy $\lambda\geq 0$, yielding a complete classification of
the set of outgoing scattering orbits. The construction is given in the
outgoing part of phase-space (a similar construction may be done in the
incoming part of phase-space). For fixed $\omega\in S^{d-1}$ and $\lambda\geq
0$ the collection of constructed orbits constitutes a smooth manifold that we
show is Lagrangian. The family of those Lagrangians can be used to study the
quantum mechanical scattering theory in the low-energy regime for the class of
potentials considered here. We devote this study to a subsequent paper.
Chinese: 对于包括吸引性库仑势在内的一个类别的负缓慢衰减势，我们研究了低能范围内的经典散射理论。我们构造了一个由初始位置$x\in \R^d$、逃逸（至无穷远）的最终方向$\omega\in S^{d-1}$和能量$\lambda\geq 0$参数化的（连续）经典轨道家族，这提供了出射散射轨道集合的完整分类。构造是在相空间的出射部分给出的（在相空间的入射部分也可以进行类似的构造）。对于固定的$\omega\in S^{d-1}$和$\lambda\geq 0$，所构造的轨道集合构成一个光滑流形，我们证明它是拉格朗日流形。这个拉格朗日家族可以用来研究考虑的势类在低能范围内的量子力学散射理论。我们将在后续的论文中进行这一研究。
|
English: The possibility of a novel type of semiconductor quantum dots obtained by
spatially modulating the spin-orbit coupling intensity in III-V
heterostructures is discussed. Using the effective mass model we predict
confined one-electron states having peculiar spin properties. Furthermore, from
mean field calculations (local-spin-density and Hartree-Fock) we find that even
two electrons could form a bound state in these dots.
Chinese: 通过在III-V异质结构中空间调制自旋轨道耦合强度，获得新型半导体量子点的可能性被讨论。利用有效质量模型，我们预测了具有特殊自旋特性的束缚单电子态。此外，从平均场计算（局域自旋密度和Hartree-Fock）中我们发现，即使两个电子也能在这些量子点中形成束缚态。
|
English: Strain engineering offers unique control to manipulate the electronic band
structure of two-dimensional materials (2DMs) resulting in an effective and
continuous tuning of the physical properties. Ad-hoc straining 2D materials has
demonstrated novel devices including efficient photodetectors at
telecommunication frequencies, enhanced-mobility transistors, and on-chip
single photon source, for example. However, in order to gain insights into the
underlying mechanism required to enhance the performance of the next-generation
devices with strain(op)tronics, it is imperative to understand the nano- and
microscopic properties as a function of a strong non-homogeneous strain. Here,
we study the strain-induced variation of local conductivity of a few-layer
transition-metal-dichalcogenide using a conductive atomic force microscopy. We
report a novel strain characterization technique by capturing the electrical
conductivity variations induced by local strain originating from surface
topography at the nanoscale, which allows overcoming limitations of existing
optical spectroscopy techniques. We show that the conductivity variations
parallel the strain deviations across the geometry predicted by molecular
dynamics simulation. These results substantiate a variation of the effective
mass and surface charge density by .026 me/% and .03e/% of uniaxial strain,
respectively. Furthermore, we show and quantify how a gradual reduction of the
conduction band minima as a function of tensile strain explains the observed
reduced effective Schottky barrier height. Such spatially-textured electronic
behavior via surface topography induced strain variations in atomistic-layered
materials at the nanoscale opens up new opportunities to control fundamental
material properties and offers a myriad of design and functional device
possibilities for electronics, nanophotonics, flextronics, or smart cloths.
Chinese: 应变工程为操纵二维材料（2DMs）的电子能带结构提供了独特的控制手段，从而有效地连续调节物理性质。定制的应变二维材料已经展示了新型器件，包括在电信频率下的高效光电探测器、增强型迁移率晶体管以及片上单光子源等。然而，为了深入了解增强下一代应变电子器件性能所需的潜在机制，有必要理解在强非均匀应变下的纳米和微观性质。在此，我们使用导电原子力显微镜研究了多层过渡金属二硫化物局部电导率的应变诱导变化。我们通过捕捉由纳米尺度表面形貌引起的局部应变所诱导的电导率变化，提出了一种新的应变表征技术，这有助于克服现有光学光谱技术存在的局限性。我们发现电导率变化与分子动力学模拟预测的几何形状上的应变偏差平行。这些结果证实了有效质量和表面电荷密度分别随单轴应变变化了0.026 me/%和0.03e/%。此外，我们展示了如何通过拉伸应变作为函数的导带最小值逐渐降低来解释观察到的有效肖特基势垒高度的降低。这种通过表面形貌诱导的应变变化在纳米尺度原子层材料中的空间纹理电子行为，为控制基本材料性质开辟了新的机会，并为电子学、纳米光子学、柔性电子学或智能织物等提供了众多设计和功能器件的可能性。
|
English: Leveraging the sensitive dependence of a giant atom's radiation rate on its
frequency [A. F. Kockum, $et~al$., Phys. Rev. A 90, 013837 (2014)], we propose
an effective magnetometer model based on single giant emitter. In this model,
the emitter's frequency is proportional to the applied bias magnetic field. The
self-interference effect causes the slope of the dissipation spectrum to vary
linearly with the number of emitter-coupling points. The giant emitter
magnetometer achieves a sensitivity as high as $10^{-8}-10^{-9}\,{\rm
T/\sqrt{Hz}}$, demonstrating the significant advantages of the
self-interference effect compared to small emitters. We hope our proposal will
expand the applications of giant emitters in precision measurement and
magnetometry.
Chinese: 利用巨原子辐射率对其频率的敏感依赖性[A. F. Kockum, $et~al$., 物理评论A 90, 013837 (2014)], 我们提出了一种基于单个巨发射器的有效磁强计模型。在该模型中，发射器的频率与施加的偏置磁场成正比。自干涉效应导致耗散谱的斜率随发射器耦合点数量的增加而线性变化。巨发射器磁强计实现了高达$10^{-8}-10^{-9}\,{\rm T/\sqrt{Hz}}$的灵敏度，展示了与小型发射器相比自干涉效应的显著优势。我们希望我们的提议能够扩展巨发射器在精密测量和磁强计领域的应用。
|
English: Understanding irreversibility in macrophysics from reversible microphysics
has been the holy grail in statistical physics ever since the mid-19th century.
Here the central question concerns the arrow of time, which boils down to
deriving macroscopic emergent irreversibility from microscopic reversible
equations of motion. As suggested by Boltzmann, this irreversibility amounts to
improbability (rather than impossibility) of the second-law-violating events.
Later studies suggest that this improbability arises from a fractal attractor
which is dynamically generated in phase space in reversible dissipative
systems. However, the same mechanism seems inapplicable to reversible
conservative systems, since a zero-volume fractal attractor is incompatible
with the nonzero phase-space volume, which is a constant of motion due to the
Liouville theorem. Here we demonstrate that in a Hamiltonian system the fractal
scaling emerges transiently over an intermediate length scale. Notably, this
transient fractality is unveiled by invoking the Loschmidt demon with an
imperfect accuracy. Moreover, we show that irreversibility from the fractality
can be evaluated by means of information theory and the fluctuation theorem.
The fractality provides a unified understanding of emergent irreversibility
over an intermediate time scale regardless of whether the underlying reversible
dynamics is dissipative or conservative.
Chinese: 自19世纪中叶以来，从可逆的微观物理学中理解不可逆的宏观物理学一直是统计物理学中的圣杯。在这里，核心问题关乎时间的箭头，这归结为从微观可逆的运动方程中推导出宏观的涌现不可逆性。正如玻尔兹曼所提出的，这种不可逆性相当于第二定律违反事件的概率性（而不是不可能性）。后来的研究表明，这种概率性源于在相空间中动态生成的分形吸引子。然而，相同的机制似乎不适用于可逆的守恒系统，因为零体积的分形吸引子与由Liouville定理导致的非零相空间体积不相容。在这里，我们证明在哈密顿系统中，分形尺度在中间长度尺度上短暂地出现。值得注意的是，这种短暂的分形性是通过引入一个不完美的洛施米特恶魔而被揭示的。此外，我们表明可以通过信息理论和涨落定理来评估由分形性产生的不可逆性。分形性为在中间时间尺度上涌现不可逆性提供了一个统一的理解，无论其背后的可逆动力学是耗散的还是守恒的。
|
English: Background: The short reads output by first- and second-generation DNA
sequencing instruments cannot completely reconstruct microbial chromosomes.
Therefore, most genomes have been left unfinished due to the significant
resources required to manually close gaps in draft assemblies.
Third-generation, single-molecule sequencing addresses this problem by greatly
increasing sequencing read length, which simplifies the assembly problem.
Results: To measure the benefit of single-molecule sequencing on microbial
genome assembly, we sequenced and assembled the genomes of six bacteria and
analyzed the repeat complexity of 2,267 complete bacteria and archaea. Our
results indicate that the majority of known bacterial and archaeal genomes can
be assembled without gaps, at finished-grade quality, using a single PacBio RS
sequencing library. These single-library assemblies are also more accurate than
typical short-read assemblies and hybrid assemblies of short and long reads.
Conclusions: Automated assembly of long, single-molecule sequencing data
reduces the cost of microbial finishing to $1,000 for most genomes, and future
advances in this technology are expected to drive the cost lower. This is
expected to increase the number of completed genomes, improve the quality of
microbial genome databases, and enable high-fidelity, population-scale studies
of pan-genomes and chromosomal organization.
Chinese: 背景：第一代和第二代DNA测序仪器产生的短读序列无法完全重建微生物染色体。因此，由于手动关闭草图组装中的间隙需要大量资源，大多数基因组都因资源限制而未能完成。
结果：为了衡量单分子测序在微生物基因组组装中的益处，我们对六种细菌的基因组进行了测序和组装，并分析了2,267个完整细菌和古菌的重复复杂性。我们的结果表明，大多数已知的细菌和古菌基因组可以使用单个PacBio RS测序库进行组装，无需间隙，达到完成级质量。这些单库组装也比典型的短读组装和短读与长读混合组装更准确。
结论：自动组装长单分子测序数据将大多数基因组的微生物完成成本降低到1000美元，预计该技术的未来进步将使成本进一步降低。这预计将增加完成基因组的数量，提高微生物基因组数据库的质量，并使全基因组水平和染色体组织的高保真、种群规模研究成为可能。
|
English: Large Language Models (LLMs) have increasingly demonstrated the ability to
facilitate the development of multi-agent systems that allow the interpretation
of thoughts and actions generated by each individual. Promising advancements
have also been made in LLM-based interaction with existing worlds, particularly
in interacting with simulated environments. This paper aims to integrate both
aforementioned topics (agents & world interaction) into a single simulation
where multiple agents can work together to solve a problem, modeling how groups
of humans can often solve problems better than individuals. By showing whether
LLMs demonstrate the synergy of human collaboration, it could lead to
advancements in the applications of LLMs. We implemented two simulations: a
physical studio apartment with two roommates, and another where agents
collaborate to complete a programming task. We provide a multi-agent framework,
discuss the performance of the agents in each simulation, and discuss potential
future additions.
Chinese: 大型语言模型（LLMs）已越来越多地展现出促进多智能体系统发展的能力，这些系统能够解读每个个体的思想与行为。在基于LLMs与现实世界的交互方面也取得了令人期待的进展，特别是在与模拟环境的交互。本文旨在将上述两个主题（智能体与世界交互）整合到单一模拟环境中，让多个智能体协同工作以解决问题，模拟人类群体通常比个体更能有效解决问题的现象。通过验证LLMs是否展现出人类协作的协同效应，这将推动LLMs应用领域的进步。我们实现了两个模拟场景：一个有两名室友的物理工作室公寓，以及一个智能体协作完成编程任务的场景。我们提供了一种多智能体框架，讨论了每个模拟场景中智能体的表现，并探讨了潜在的后续改进方向。
|
English: With the advent of post-quantum cryptography (PQC) standards, it has become
imperative for resource-constrained devices (RCDs) in the Internet of Things
(IoT) to adopt these quantum-resistant protocols. However, the high
computational overhead and the large key sizes associated with PQC make direct
deployment on such devices impractical. To address this challenge, we propose
an edge computing-enabled PQC framework that leverages a physical-layer
security (PLS)-assisted offloading strategy, allowing devices to either offload
intensive cryptographic tasks to a post-quantum edge server (PQES) or perform
them locally. Furthermore, to ensure data confidentiality within the edge
domain, our framework integrates two PLS techniques: offloading RCDs employ
wiretap coding to secure data transmission, while non-offloading RCDs serve as
friendly jammers by broadcasting artificial noise to disrupt potential
eavesdroppers. Accordingly, we co-design the computation offloading and PLS
strategy by jointly optimizing the device transmit power, PQES computation
resource allocation, and offloading decisions to minimize overall latency under
resource constraints. Numerical results demonstrate significant latency
reductions compared to baseline schemes, confirming the scalability and
efficiency of our approach for secure PQC operations in IoT networks.
Chinese: 随着后量子密码学（PQC）标准的出现，对于物联网（IoT）中的资源受限设备（RCD）来说，采用这些抗量子协议变得至关重要。然而，与PQC相关的高计算开销和大型密钥大小使得在这样设备上的直接部署不切实际。为了应对这一挑战，我们提出一个边缘计算支持的PQC框架，该框架利用物理层安全（PLS）辅助的卸载策略，允许设备将密集的加密任务卸载到后量子边缘服务器（PQES）或本地执行。此外，为了确保边缘域内的数据机密性，我们的框架集成了两种PLS技术：卸载的RCD采用窃听编码来保护数据传输，而非卸载的RCD通过广播人工噪声充当友好干扰器，以干扰潜在的窃听者。因此，我们通过联合优化设备发射功率、PQES计算资源分配和卸载决策来协同设计计算卸载和PLS策略，以在资源受限的情况下最小化整体延迟。数值结果表明，与基线方案相比，我们的方案显著降低了延迟，证实了其在物联网网络中进行安全PQC操作的可扩展性和效率。
|
English: We derive a universal formula for the asymptotic growth of the mean value of
three-point coefficient for Warped Conformal Field Theories (WCFTs), and
provide a holographic calculation in BTZ black holes. WCFTs are two dimensional
quantum field theories featuring a chiral Virasoro and U(1) Kac-Moody algebra,
and are conjectured to be holographically dual to quantum gravity on
asymptotically AdS$_3$ spacetime with
Comp$\grave{\mathrm{e}}$re-Song-Strominger boundary conditions. The WCFT
calculation amounts to the calculation of one-point functions on torus, whose
high temperature limit can be approximated by using modular covariance of WCFT,
similar to the derivation of Cardy formula. The bulk process is given by a
tadpole diagram, with a massive spinning particle propagates from the infinity
to the horizon, and splits into particle and antiparticle which annihilate
after going around the horizon of BTZ black holes. The agreement between the
bulk and WCFT calculations indicates that the black hole geometries in
asymptotically AdS$_3$ spacetimes can emerge upon coarse-graining over
microstates in WCFTs, similar to the results of Kraus and Maloney in the
context of AdS/CFT[arXiv:1608.03284].
Chinese: 我们推导出关于扭曲共形场论（WCFTs）三点系数平均值渐近增长的通用公式，并在BTZ黑洞中提供了一个全息计算。WCFTs是具有手性Virasoro和U(1) Kac-Moody代数的二维量子场论，并且被推测在渐近AdS$_3$时空下，具有Comp$\grave{\mathrm{e}}$re-Song-Strominger边界条件时，与量子引力全息对应。WCFT的计算相当于在环面上计算单点函数，其高温极限可以通过使用WCFT的模协变性来近似，类似于Cardy公式的推导。实体过程由一个蝌蚪图给出，一个有质量的旋转粒子从无穷远传播到视界，并在绕过BTZ黑洞的视界后分裂成粒子和反粒子，它们随后相互湮灭。实体与WCFT计算之间的一致性表明，在渐近AdS$_3$时空中的黑洞几何可以通过对WCFT中的微观态进行粗粒化而产生，这与Kraus和Maloney在AdS/CFT背景下的结果相似[arXiv:1608.03284]。
|
English: Using x-ray resonant magnetic scattering and x-ray magnetic circular
dichroism, techniques that are element specific, we have elucidated the role of
Ho3+ in multiferroic HoMnO3. In zero field, Ho3+ orders antiferromagnetically
with moments aligned along the hexagonal c direction below 40 K, and undergoes
a transition to another magnetic structure below 4.5 K. In applied electric
fields of up to 1x10^7 V/m, the magnetic structure of Ho3+ remains unchanged.
Chinese: 利用X射线共振磁散射和X射线磁圆二色性这两种元素特异性技术，我们阐明了Ho3+在多铁性HoMnO3中的作用。在零场下，Ho3+在低于40K时沿六角形c轴方向反铁磁有序排列，并在低于4.5K时转变为另一种磁结构。在高达1×10^7 V/m的电场下，Ho3+的磁结构保持不变。
|
English: We single out the Starobinsky model and its extensions among generic $f(R)$
gravity as attractors at large field values for chaotic inflation. Treating a
$R^3$ curvature term as a perturbation of the Starobinsky model, we impose the
phenomenological bounds on the additional term satisfying the successful
inflationary predictions. We find that the scalar spectral index can vary in
both the red or blue tilted direction, depending on the sign of the coefficient
of the $R^3$ term, whereas the tensor-to-scalar ratio is less affected in the
Planck-compatible region. We also discuss the role of higher order curvature
term for stability and the reheating dynamics for the unambiguous prediction
for the number of efoldings up to the $R^3$ term.
Chinese: 我们在通用的$f(R)$引力中特别关注Starobinsky模型及其扩展，将其视为混沌膨胀在大场值下的吸引子。将$R^3$曲率项视为Starobinsky模型的扰动，我们对满足成功膨胀预测的额外项施加了现象学界限。我们发现标量谱指数可以在红倾斜或蓝倾斜方向上变化，这取决于$R^3$项系数的符号，而张量到标量的比在普朗克兼容区域内受影响较小。我们还讨论了高阶曲率项在稳定性中的作用以及重加热动力学对于明确预测直到$R^3$项的折叠次数的重要性。
|
English: The nuclear spin of a phosphorus atom in silicon has been used as a quantum
bit in various quantum-information experiments. It has been proposed that this
nuclear-spin qubit can be efficiently controlled by an ac electric field, when
embedded in a two electron dot-donor setup subject to intrinsic or artificial
spin-orbit interaction. Exposing the qubit to control electric fields in that
setup exposes it to electric noise as well. In this work, we describe the
effect of electric noise mechanisms, such as phonons and $1/f$ charge noise,
and estimate the corresponding decoherence time scales of the nuclear-spin
qubit. We identify a promising parameter range where the electrical
single-qubit operations are at least an order of magnitude faster then the
decoherence. In this regime, decoherence is dominated by dephasing due to $1/f$
charge noise. Our results facilitate the optimized design of nanostructures to
demonstrate electrically driven nuclear spin resonance.
Chinese: 硅中磷原子的核自旋已被用作量子信息实验中的量子比特。有提议称，当这种核自旋量子比特嵌入到受到固有或人工自旋-轨道相互作用的二电子点供体设置中时，可以通过交流电场有效地对其进行控制。在该设置中将量子比特暴露于控制电场的同时，也会使其暴露于电噪声。在这项工作中，我们描述了电噪声机制，如声子和$1/f$电荷噪声的影响，并估计了相应的核自旋量子比特的相干时间尺度。我们确定了一个有前景的参数范围，其中电单量子比特操作至少比相干快一个数量级。在这个范围内，相干主要由$1/f$电荷噪声引起的去相位主导。我们的结果有助于优化纳米结构的设计，以展示电驱动核自旋共振。
|
English: The explorative mind-map is a dynamic framework, that emerges automatically
from the input, it gets. It is unlike a verificative modeling system where
existing (human) thoughts are placed and connected together. In this regard,
explorative mind-maps change their size continuously, being adaptive with
connectionist cells inside; mind-maps process data input incrementally and
offer lots of possibilities to interact with the user through an appropriate
communication interface. With respect to a cognitive motivated situation like a
conversation between partners, mind-maps become interesting as they are able to
process stimulating signals whenever they occur. If these signals are close to
an own understanding of the world, then the conversational partner becomes
automatically more trustful than if the signals do not or less match the own
knowledge scheme. In this (position) paper, we therefore motivate explorative
mind-maps as a cognitive engine and propose these as a decision support engine
to foster trust.
Chinese: 探索性思维导图是一个动态框架，它自动从输入中产生。它与验证性建模系统不同，后者是将现有的（人类）思想放置并连接在一起。在这方面，探索性思维导图会持续改变其大小，内部具有连接主义细胞，使其具有适应性；思维导图会增量处理数据输入，并通过适当的通信界面为用户提供大量互动的可能性。在认知动机情境，如伙伴之间的对话中，思维导图变得有趣，因为它们能够处理随时出现的刺激信号。如果这些信号接近自己对世界的理解，那么对话伙伴就会自动比信号不匹配或匹配度较低时更加值得信赖。因此，在这篇（论文）中，我们倡导探索性思维导图作为一种认知引擎，并提议将其作为决策支持引擎来促进信任。
|
English: It is shown that superefficient Monte Carlo computations can be carried out
by using chaotic dynamical systems as non-uniform random-number generators.
Here superefficiency means that the expectation value of the square of the
error decreases to 0 as 1/N^{2} with N successive observations for N->
infinity, whereas the conventional Monte Carlo simulation gives the square of
the error in the order 1/N. The order of N in the error convergence speed of
superefficient Monte Carlo computations does not depend on the dimensionality
of the problems. By deriving a necessary and sufficient condition for the
superefficiency, it is shown that such high-performance Monte Carlo simulations
can be carried out only if there exists a strong correlation of chaotic
dynamical variables.
Chinese: 研究表明，可以使用混沌动力学系统作为非均匀随机数生成器来执行超高效的蒙特卡洛计算。在这里，超高效意味着随着N次连续观察N趋于无穷大，误差平方的期望值以1/N^2的速度下降到0，而传统的蒙特卡洛模拟给出的误差平方在1/N的量级。在超高效蒙特卡洛计算的误差收敛速度中，N的阶数不依赖于问题的维度。通过推导出超高效的必要和充分条件，表明只有当混沌动力学变量之间存在强相关性时，才能进行这种高性能的蒙特卡洛模拟。
|
English: I investigate the possibility of constraining the flux of the lens (i.e.,
host star) for the types of planetary systems the Korean Microlensing Telescope
Network is predicted to find. I examine the potential to obtain lens flux
measurements by 1) imaging a lens once it is spatially resolved from the
source, 2) measuring the elongation of the point spread function of the
microlensing target (lens+source) when the lens and source are still
unresolved, and 3) taking prompt follow-up photometry. In each case I simulate
observing programs for a representative example of current ground-based
adaptive optics (AO) facilities (specifically NACO on VLT), future ground-based
AO facilities (GMTIFS on GMT), and future space telescopes (NIRCAM on $JWST$).
Given the predicted distribution of relative lens-source proper motions, I find
that the lens flux could be measured to a precision of $\sigma_{H_{\ell}} \leq
0.1$ for $\gtrsim$60$\%$ of planet detections $\geq$5 years after each
microlensing event, for a simulated observing program using GMT that images
resolved lenses. NIRCAM on $JWST$ would be able to carry out equivalently
high-precision measurements for $\sim$28$\%$ of events $\Delta t$ = 10 years
after each event by imaging resolved lenses. I also explore the effects various
blend components would have on the mass derived from prompt follow-up
photometry, including companions to the lens, companions to the source, and
unassociated interloping stars. I find that undetected blend stars would cause
catastrophic failures (i.e., $>$50$\%$ fractional uncertainty in the inferred
lens mass) for $\lesssim$(16$\cdot f_{\rm bin})\%$ of planet detections, where
$f_{\rm bin}$ is the binary fraction, with the majority of these failures
occurring for host stars with mass $\lesssim$0.3$M_{\odot}$.
Chinese: 我研究了限制透镜（即宿主恒星）通量的可能性，这是韩国微引力透镜望远镜网络预计会发现的各种行星系统。我考察了通过以下方式获取透镜通量测量的潜力：1）在透镜从源中空间分辨后进行成像；2）在透镜和源仍然无法分辨时测量微引力透镜目标（透镜+源）的点扩散函数的延展性；3）进行快速后续光度测量。在每种情况下，我模拟了当前地基自适应光学（AO）设施（特别是VLT上的NACO）、未来地基AO设施（GMT上的GMTIFS）和未来空间望远镜（JWST上的NIRCAM）的代表性观测计划。根据预计的相对透镜-源自行分布，我发现对于每个微引力透镜事件发生后至少5年检测到的行星，使用GMT成像已分辨透镜的模拟观测计划可以将透镜通量测量精度控制在$\sigma_{H_{\ell}} \leq 0.1$，适用于$\gtrsim$60%的行星探测事件。JWST上的NIRCAM通过成像已分辨透镜，能够在每个事件发生后$\Delta t$ = 10年的约28%的事件中执行同等高精度的测量。我还探讨了各种混合成分对快速后续光度测量推导出的质量的影响，包括透镜的伴星、源的伴星以及无关的干扰星。我发现未检测到的混合星会导致灾难性失败（即推断的透镜质量存在>50%的分数不确定性），这对于$\lesssim$(16$\cdot f_{\rm bin})\%$的行星探测事件发生，其中$f_{\rm bin}$是双星分数，且这些失败中的大多数发生在质量$\lesssim$0.3$M_{\odot}$的主星上。
|
English: While ubiquitous, textual sources of information such as company reports,
social media posts, etc. are hardly included in prediction algorithms for time
series, despite the relevant information they may contain. In this work, openly
accessible daily weather reports from France and the United-Kingdom are
leveraged to predict time series of national electricity consumption, average
temperature and wind-speed with a single pipeline. Two methods of numerical
representation of text are considered, namely traditional Term Frequency -
Inverse Document Frequency (TF-IDF) as well as our own neural word embedding.
Using exclusively text, we are able to predict the aforementioned time series
with sufficient accuracy to be used to replace missing data. Furthermore the
proposed word embeddings display geometric properties relating to the behavior
of the time series and context similarity between words.
Chinese: 尽管公司报告、社交媒体帖子等信息来源无处不在，但它们几乎未被包含在时间序列预测算法中，尽管它们可能包含相关信息。在这项工作中，我们利用法国和联合王国的公开可访问的每日天气预报来预测国家电力消耗、平均温度和风速的时间序列，使用单一的管道。考虑了两种文本的数值表示方法，即传统的词频-逆文档频率（TF-IDF）以及我们自己的神经词嵌入。仅使用文本，我们能够以足够的准确性预测上述时间序列，以用于替换缺失数据。此外，所提出的词嵌入显示出与时间序列行为和词语之间上下文相似性相关的几何属性。
|
English: A key challenge in program synthesis is the astronomical size of the search
space the synthesizer has to explore. In response to this challenge, recent
work proposed to guide synthesis using learned probabilistic models. Obtaining
such a model, however, might be infeasible for a problem domain where no
high-quality training data is available. In this work we introduce an
alternative approach to guided program synthesis: instead of training a model
ahead of time we show how to bootstrap one just in time, during synthesis, by
learning from partial solutions encountered along the way. To make the best use
of the model, we also propose a new program enumeration algorithm we dub guided
bottom-up search, which extends the efficient bottom-up search with guidance
from probabilistic models.
We implement this approach in a tool called Probe, which targets problems in
the popular syntax-guided synthesis (SyGuS) format. We evaluate Probe on
benchmarks from the literature and show that it achieves significant
performance gains both over unguided bottom-up search and over a
state-of-the-art probability-guided synthesizer, which had been trained on a
corpus of existing solutions. Moreover, we show that these performance gains do
not come at the cost of solution quality: programs generated by Probe are only
slightly more verbose than the shortest solutions and perform no unnecessary
case-splitting.
Chinese: 程序合成中的一个关键挑战是合成器必须探索的搜索空间极其庞大。为应对这一挑战，近期研究提出使用学习到的概率模型来指导合成。然而，在缺乏高质量训练数据的问题领域中，获取此类模型可能并不可行。在这项工作中，我们引入了一种指导程序合成的替代方法：不是提前训练模型，而是展示如何在合成过程中实时启动模型，通过学习途中遇到的局部解来实现。为充分利用模型，我们还提出了一种新的程序枚举算法，我们称之为引导自底向上搜索，该算法在高效自底向上搜索的基础上，扩展了概率模型的指导功能。
我们使用名为Probe的工具实现了这一方法，该工具针对流行的语法引导合成（SyGuS）格式的 问题。我们在文献中的基准测试上评估了Probe，并证明它在未受引导的自底向上搜索和受概率引导的合成器（该合成器基于现有解语料库训练）上均实现了显著的性能提升。此外，我们证明这些性能提升并未以牺牲解质量为代价：Probe生成的程序仅比最短解稍长，且不会进行不必要的分支判断。
|
English: The Strong Law of Large Numbers (SLLN) for random variables or random vectors
with different mathematical expectations easily reduces by means of shifts to
SLLN for random variables or random vectors whose mathematical expectations are
equal to zero. The situation changes for random sets, where shifts cannot
reduce sets of more than one point to the set $\{0\}$. We study effects that
appear because of this difference.
Chinese: 大数定律（SLLN）对于具有不同数学期望的随机变量或随机向量，可以通过平移轻松地转化为具有数学期望等于零的随机变量或随机向量的SLLN。对于随机集的情况则不同，平移不能将多于一个点的集合减少到集合 $\{0\}$。我们研究由此差异产生的影响。
|
English: Photon-mediated interactions within an excited ensemble of emitters can
result in Dicke superradiance, where the emission rate is greatly enhanced,
manifesting as a high-intensity burst at short times. The superradiant burst is
most commonly observed in systems with long-range interactions between the
emitters, although the minimal interaction range remains unknown. Here, we put
forward a new theoretical method to bound the maximum emission rate by upper
bounding the spectral radius of an auxiliary Hamiltonian. We harness this tool
to prove that for an arbitrary ordered array with only nearest-neighbor
interactions in all dimensions, a superradiant burst is not physically
observable. We show that Dicke superradiance requires minimally the inclusion
of next-nearest-neighbor interactions. For exponentially decaying interactions,
the critical coupling is found to be asymptotically independent of the number
of emitters in all dimensions, thereby defining the threshold interaction range
where the collective enhancement balances out the decoherence effects. Our
findings provide key physical insights to the understanding of collective decay
in many-body quantum systems, and the designing of superradiant emission in
physical systems for applications such as energy harvesting and quantum
sensing.
Chinese: 光子介导的激发发射体集合内的相互作用可能导致狄克超辐射，其中发射率大大增强，表现为短时间内的高强度爆发。超辐射爆发最常见于发射体之间存在长程相互作用的系统中，尽管最小相互作用范围尚不清楚。在这里，我们提出了一种新的理论方法，通过上界一个辅助哈密顿量的谱半径来界定最大发射率。我们利用这个工具证明，对于所有维度上只有最近邻相互作用的任意有序阵列，超辐射爆发在物理上是不可观察的。我们表明，狄克超辐射至少需要包含次近邻相互作用。对于指数衰减的相互作用，临界耦合被发现与所有维度上的发射体数量渐近无关，从而定义了集体增强与去相干效应平衡的阈值相互作用范围。我们的发现为理解多体量子系统的集体衰变提供了关键的物理洞见，并为在物理系统中设计超辐射发射以应用于能量收集和量子传感等领域提供了指导。
|
English: We study the spectral signatures arising from cooling and recombination of an
interstellar medium whose equilibrium state has been altered over \sim 100 pc
by the radiation of a Gamma-Ray Burst (GRB) and its afterglow. We identify
signatures in the line diagnostics which are indicative of a photo-ionized GRB
remnant which is \la 5 x 10^4 years old . We estimate that at least a few such
remnants should be detectable in the Virgo cluster of galaxies. If the
gamma-ray emission from GRBs is beamed to a fraction f_b of their sky, then the
expected number of Virgo remnants is larger by a factor of f_b^{-1}. Virgo
remnants can be resolved with arcsecond imaging, and are likely to be
center-filled using narrow-band filters of high ionization lines (such as [O
III] \lambda5007 or He II \lambda4686), and limb-brightened for low-ionization
lines (such as [S II] \lambda6717). The non-relativistic blast wave might be
visible separately, since it does not reach the outer edge of these young
photo-ionized remnants. The remnants should show evidence for ionization cones
if the prompt or afterglow UV emission from GRBs is beamed.
Chinese: 我们研究了由于伽马射线暴（GRB）及其余辉的辐射，使得星际介质的平衡状态在约100 pc范围内被改变后，冷却和再组合产生的光谱特征。我们在线诊断中识别出特征，这些特征表明存在一个年龄小于5 x 10^4年的光电离GRB残留物。我们估计，在室女座星系团中至少可以检测到几个这样的残留物。如果GRB的伽马射线发射被指向其天空的f_b部分，那么预期的室女座残留物数量将增加f_b的倒数倍。室女座残留物可以用角秒成像分辨，并且很可能会使用高电离线的窄带滤光片（如[O III] λ5007或He II λ4686）进行中心填充，对于低电离线（如[S II] λ6717）则可能边缘变亮。非相对论性的冲击波可能可以单独观察到，因为它没有达到这些年轻光电离残留物的外缘。如果GRB的prompt或余辉紫外发射被指向，这些残留物应该显示出电离锥的证据。
|
English: Ovoids of the hyperbolic quadric $Q^+(7,q)$ of $\mathrm{PG}(7,q)$ have been
extensively studied over the past 40 years, partly due to their connections
with other combinatorial objects. It is well known that the points of an ovoid
of $Q^+(7,q)$ can be parametrized by three polynomials $f_1(X,Y,Z)$,
$f_2(X,Y,Z)$, $f_3(X,Y,Z)$. In this paper, we classify ovoids of $Q^+(7,q)$ of
low degree, specifically under the assumption that $f_1(X,Y,Z)$, $f_2(X,Y,Z)$,
$f_3(X,Y,Z)$ have degree at most 3. Our approach relies on the analysis of an
algebraic hypersurface associated with the ovoid.
Chinese: $\mathrm{PG}(7,q)$中的双曲二次超曲面$Q^+(7,q)$在过去40年中得到了广泛的研究，部分原因是它们与其他组合对象之间的联系。众所周知，$Q^+(7,q)$的卵形点的参数化可以通过三个多项式$f_1(X,Y,Z)$、$f_2(X,Y,Z)$、$f_3(X,Y,Z)$来实现。在本文中，我们分类了低度数的$Q^+(7,q)$卵形，具体来说，是在假设$f_1(X,Y,Z)$、$f_2(X,Y,Z)$、$f_3(X,Y,Z)$的次数最多为3的情况下。我们的方法依赖于与卵形相关联的代数超曲面的分析。
|
English: Sharp large deviation results of Bahadur-Ranga Rao type are provided for the
$q$-norm of random vectors distributed on the $\ell _{p}^{n}$-ball
${\mathbb{B}}^{n}_{p}$ according to the cone probability measure or the uniform
distribution for $1 \le q<p < \infty $, thereby furthering previous large
deviation results by Kabluchko, Prochno and Th\"{a}le in the same setting.
These results are then applied to deduce sharp asymptotics for intersection
volumes of different $\ell _{p}^{n}$-balls in the spirit of Schechtman and
Schmuckenschl\"{a}ger, and for the length of the projection of an $\ell
_{p}^{n}$-ball onto a line with uniform random direction. The sharp large
deviation results are proven by providing convenient probabilistic
representations of the $q$-norms, employing local limit theorems to approximate
their densities, and then using geometric results for asymptotic expansions of
Laplace integrals to integrate these densities and derive concrete probability
estimates.
Chinese: 为在${\mathbb{B}}^{n}_{p}$-球${\mathbb{B}}^{n}_{p}$上按锥概率测度或均匀分布分布的随机向量的$q$-范数提供了Bahadur-Ranga Rao类型的锐利大偏差结果，从而进一步扩展了Kabluchko、Prochno和Th\"{a}le在相同设置下的大偏差结果。然后，将这些结果应用于推导不同${\ell _{p}^{n}}$-球的交叠体积的锐利渐近性质，以及${\ell _{p}^{n}}$-球在具有均匀随机方向的直线上投影的长度。通过提供$q$-范数的方便概率表示，利用局部极限定理来近似它们的密度，然后使用几何结果对Laplace积分的渐近展开进行积分，从而得到这些密度的具体概率估计，从而证明了锐利的大偏差结果。
|
English: We investigate various aspects of the integrability of the vertex models
associated to the $D_n^2$ affine Lie algebra with open boundaries. We first
study the solutions of the corresponding reflection equation compatible with
the minimal symmetry of this system. We find three classes of general
solutions, one diagonal solution and two non-diagonal families with a free
parameter. Next we perform the Bethe ansatz analysis for some of the associated
open $D_2^2$ spin chains and we identify the boundary having quantum group
invariance. We also discuss a new $D_2^2$ $R$-matrix.
Chinese: 我们研究了与D_n^2型 affine 李代数相关联、具有开放边界的顶点模型的积分性质。首先，我们研究了与该系统最小对称性相容的相应反射方程的解。我们发现三类通解：一个对角解和两个具有自由参数的非对角解族。接下来，我们对部分相关的开放D_2^2自旋链进行了Bethe ansatz分析，并识别出具有量子群不变性的边界。我们还讨论了一个新的D_2^2 R矩阵。
|
English: Developing methods to process irregularly structured data is crucial in
applications like gene-regulatory, brain, power, and socioeconomic networks.
Graphs have been the go-to algebraic tool for modeling the structure via nodes
and edges capturing their interactions, leading to the establishment of the
fields of graph signal processing (GSP) and graph machine learning (GML). Key
graph-aware methods include Fourier transform, filtering, sampling, as well as
topology identification and spatiotemporal processing. Although versatile,
graphs can model only pairwise dependencies in the data. To this end,
topological structures such as simplicial and cell complexes have emerged as
algebraic representations for more intricate structure modeling in data-driven
systems, fueling the rapid development of novel topological-based processing
and learning methods. This paper first presents the core principles of
topological signal processing through the Hodge theory, a framework
instrumental in propelling the field forward thanks to principled connections
with GSP-GML. It then outlines advances in topological signal representation,
filtering, and sampling, as well as inferring topological structures from data,
processing spatiotemporal topological signals, and connections with topological
machine learning. The impact of topological signal processing and learning is
finally highlighted in applications dealing with flow data over networks,
geometric processing, statistical ranking, biology, and semantic communication.
Chinese: 开发处理非规则结构数据的方法在基因调控、大脑、电力和社会经济网络等应用中至关重要。图作为通过节点和边建模结构的首选代数工具，捕捉其交互作用，从而催生了图信号处理（GSP）和图机器学习（GML）领域。关键图感知方法包括傅里叶变换、滤波、采样，以及拓扑识别和时空处理。尽管功能多样，图只能建模数据的成对依赖。为此，单纯复形和细胞复形等拓扑结构作为数据驱动系统中更复杂结构建模的代数表示应运而生，推动了基于拓扑的新型处理和学习方法的快速发展。本文首先通过霍奇理论阐述拓扑信号处理的核心原理，该框架因与GSP-GML的原则性联系而推动该领域发展。接着概述了拓扑信号表示、滤波、采样，以及从数据中推断拓扑结构、处理时空拓扑信号，与拓扑机器学习的联系等进展。最后强调拓扑信号处理与学习在网络流量数据、几何处理、统计排序、生物学和语义通信等应用中的影响。
|
English: We give an alternative proof and improve upon a result of S.M. Kozlov
\cite{ko}. It deals with the asymptotic of the integrated density of states of
the acoustic operator $\displaystyle H_\omega=-\nabla\rho_\omega\nabla$, at the
bottom of the spectrum.
Chinese: 我们提供了一个替代的证明，并改进了S.M. Kozlov
\cite{ko}的一个结果。它涉及到声学算子 $\displaystyle H_\omega=-\nabla\rho_\omega\nabla$ 在谱底部的积分态密度的渐近性质。
|
English: This note provides a succinct proof of a 1973 theorem of Lieb that
establishes the concavity of a certain trace function. The development relies
on a deep result from quantum information theory, the joint convexity of
quantum relative entropy, as well as a recent argument due to Carlen and Lieb.
Chinese: 本笔记提供了一个简明的证明，证明了Lieb在1973年提出的一个定理，该定理确立了某个迹函数的凹性。这一证明依赖于量子信息理论中的一个深刻结果——量子相对熵的联合凸性，以及Carlen和Lieb最近的一个论点。
|
English: We consider the problem of combining data from observational and experimental
sources to make causal conclusions. This problem is increasingly relevant, as
the modern era has yielded passive collection of massive observational datasets
in areas such as e-commerce and electronic health. These data may be used to
supplement experimental data, which is frequently expensive to obtain. In
Rosenman et al. (2018), we considered this problem under the assumption that
all confounders were measured. Here, we relax the assumption of
unconfoundedness. To derive combined estimators with desirable properties, we
make use of results from the Stein Shrinkage literature. Our contributions are
threefold. First, we propose a generic procedure for deriving shrinkage
estimators in this setting, making use of a generalized unbiased risk estimate.
Second, we develop two new estimators, prove finite sample conditions under
which they have lower risk than an estimator using only experimental data, and
show that each achieves a notion of asymptotic optimality. Third, we draw
connections between our approach and results in sensitivity analysis, including
proposing a method for evaluating the feasibility of our estimators.
Chinese: 我们考虑了从观测和实验来源结合数据以得出因果结论的问题。这个问题越来越相关，因为现代时代在电子商务和电子健康等领域产生了大量观测数据集的被动收集。这些数据可以用来补充实验数据，而实验数据通常获取成本高昂。在Rosenman等人（2018）的研究中，我们假设所有混杂因素都被测量，来考虑了这个问题。在这里，我们放宽了无混杂性的假设。为了推导出具有理想性质的组合估计量，我们利用了Stein收缩文献中的结果。我们的贡献有三点。首先，我们提出了一种在当前环境中推导收缩估计量的通用方法，该方法利用了广义无偏风险估计。其次，我们开发了两种新的估计量，证明了在有限样本条件下，它们的风险低于仅使用实验数据的估计量，并表明每个都实现了渐近最优性的概念。第三，我们将我们的方法与敏感性分析中的结果联系起来，包括提出了一种评估我们估计量可行性的方法。
|
English: Youth unemployment rates are still in alerting levels for many countries,
among which Italy. Direct consequences include poverty, social exclusion, and
criminal behaviours, while negative impact on the future employability and wage
cannot be obscured. In this study, we employ survey data together with social
media data, and in particular likes on Facebook Pages, to analyse personality,
moral values, but also cultural elements of the young unemployed population in
Italy. Our findings show that there are small but significant differences in
personality and moral values, with the unemployed males to be less agreeable
while females more open to new experiences. At the same time, unemployed have a
more collectivist point of view, valuing more in-group loyalty, authority, and
purity foundations. Interestingly, topic modelling analysis did not reveal
major differences in interests and cultural elements of the unemployed.
Utilisation patterns emerged though; the employed seem to use Facebook to
connect with local activities, while the unemployed use it mostly as for
entertainment purposes and as a source of news, making them susceptible to
mis/disinformation. We believe these findings can help policymakers get a
deeper understanding of this population and initiatives that improve both the
hard and the soft skills of this fragile population.
Chinese: 青年失业率对于许多国家来说仍然处于警报水平，其中就包括意大利。直接后果包括贫困、社会排斥和犯罪行为，对未来就业能力和工资的负面影响也无法忽视。在本研究中，我们结合调查数据和社交媒体数据，特别是Facebook页面的点赞数据，来分析意大利青年失业者的个性、道德价值观，以及文化元素。我们的研究发现，在个性和道德价值观方面存在微小但显著的区别，失业的男性更不易相处，而女性则更愿意接受新经验。同时，失业者持有更集体主义的角度，更重视团体忠诚、权威和纯洁性基础。有趣的是，主题建模分析并未揭示失业者在兴趣和文化元素方面的主要差异。然而，使用模式出现了；在职者似乎使用Facebook来参与当地活动，而失业者则主要将其用于娱乐目的和新闻来源，这使得他们容易受到错误/虚假信息的侵害。我们相信这些发现可以帮助政策制定者更深入地了解这一群体，并采取旨在提高这一脆弱群体硬技能和软技能的举措。
|
English: We present the general discussion on the inflection point inflation with
small or large inflaton fields and show the effects of reheating dynamics on
the inflationary predictions. In order to compare the model predictions with
precisely measured CMB anisotropies and constrain the inflation models, the
knowledge of the reheating dynamics is required. Inflection point inflation
extended to the trans-Planckian regime can accommodate a sizable
tensor-to-scalar ratio at the detectable level in the future CMB experiments.
Chinese: 我们介绍了小或大 inflaton 场在拐点膨胀中的一般讨论，并展示了再加热动力学对膨胀预测的影响。为了将模型预测与精确测量的 CMB 各向异性进行比较，并限制膨胀模型，需要了解再加热动力学。将拐点膨胀延伸到超普朗克领域可以容纳一个在未来的 CMB 实验中可检测到的可观的张量与标量比率。
|
English: We report observations of $\eta$ Carinae obtained with ALMA in the continuum
of 100, 230, 280 and 660 GHz in 2012 November, with a resolution that varied
from 2.88" to 0.45" for the lower and higher frequencies respectively. The
source is not resolved, even at the highest frequency; its spectrum is
characteristic of thermal bremsstrahlung of a compact source, but different
from the spectrum of optically thin wind. The recombination lines H42$\alpha$,
He42$\alpha$, H40$\alpha$, He40$\alpha$, H50$\beta$, H28$\alpha$, He28$\alpha$,
H21$\alpha$ and He21$\alpha$ were also detected and their intensities reveal
non local thermodynamic equilibrium (NLTE) effects. We found that the line
profiles could only be fit by an expanding shell of dense and ionized gas,
which produces a slow shock in the surroundings of $\eta$ Carinae. Combined
with fittings to the continuum, we were able to constrain the shell size,
radius, density, temperature and velocity. The detection of the He
recombination lines is compatible with the high temperature gas and requires a
high energy ionizing photon flux, which must be provided by the companion star.
The mass loss rate and wind velocity, necessary to explain the formation of the
shell, are compatible with a LBV eruption. The position, velocity and physical
parameters of the shell coincide with those of the Weigelt blobs. The dynamics
found for the expanding shell corresponds to matter ejected by $\eta$ Carinae
in 1941, in an event similar to that which formed the Little Homunculus ; for
that reason we called the new ejecta the "Baby Homunculus".
Chinese: 我们报告了2012年11月使用ALMA在100、230、280和660 GHz连续波段的$\eta$ Carinae观测结果，其分辨率分别从2.88"到0.45"不等。即使在最高频率下，源也没有被分辨出来；其光谱特征为紧凑源的热辐射，但与光学薄风的光谱不同。H42α、He42α、H40α、He40α、H50β、H28α、He28α、H21α和He21α的再结合线也被检测到，它们的强度揭示了非局部热力学平衡（NLTE）效应。我们发现，只有通过一个膨胀的致密和电离气体壳层才能拟合出线形，这个壳层在$\eta$ Carinae周围产生缓慢的冲击。结合对连续波段的拟合，我们能够约束壳层的大小、半径、密度、温度和速度。He再结合线的检测与高温气体相容，需要高能量的电离光子通量，这必须由伴星提供。为了解释壳层的形成，所需的物质损失率和风速度与LBV爆发相容。壳层的位置、速度和物理参数与Weigelt球团相一致。对于膨胀壳层的动力学发现对应于1941年由$\eta$ Carinae喷射出的物质，在一个类似于形成小生物体的过程中；因此，我们将新的喷射物称为“婴儿生物体”。
|
English: Training generative models like Generative Adversarial Network (GAN) is
challenging for noisy data. A novel curriculum learning algorithm pertaining to
clustering is proposed to address this issue in this paper. The curriculum
construction is based on the centrality of underlying clusters in data points.
The data points of high centrality takes priority of being fed into generative
models during training. To make our algorithm scalable to large-scale data, the
active set is devised, in the sense that every round of training proceeds only
on an active subset containing a small fraction of already trained data and the
incremental data of lower centrality. Moreover, the geometric analysis is
presented to interpret the necessity of cluster curriculum for generative
models. The experiments on cat and human-face data validate that our algorithm
is able to learn the optimal generative models (e.g. ProGAN) with respect to
specified quality metrics for noisy data. An interesting finding is that the
optimal cluster curriculum is closely related to the critical point of the
geometric percolation process formulated in the paper.
Chinese: 将生成模型（如生成对抗网络GAN）应用于含噪声数据时存在挑战。本文提出了一种基于聚类的课程学习算法来解决这个问题。课程构建基于数据点下聚类的中心性，中心性高的数据点在训练过程中优先被输入生成模型。为使算法可扩展至大规模数据，设计了活跃集机制，即每次训练仅在一个包含少量已训练数据和低中心性增量数据的活跃子集上进行。此外，本文还通过几何分析阐释了聚类课程对生成模型的必要性。在猫和人类面部数据的实验验证了该算法能够学习最优生成模型（如ProGAN），并针对含噪声数据生成特定质量指标下的最优模型。一个有趣发现是，最优聚类课程与本文提出的几何渗透过程的临界点密切相关。
|
English: The complete on-shell action of topological Einstein-Maxwell gravity in
four-dimensions is presented. It is shown explicitly how this theory for SU(2)
holonomy manifolds arises from four-dimensional Euclidean N=2 supergravity. The
twisted local BRST symmetries and twisted local Lorentz symmetries are given
and the action and stress tensor are shown to be BRST-exact. A set of
BRST-invariant topological operators is given. The vector and antisymmetric
tensor twisted supersymmetries and their algebra are also found.
Chinese: 四维空间中拓扑爱因斯坦-麦克斯韦引力的完整壳上作用量被提出。明确展示了这种理论如何从四维欧几里得N=2超引力中产生。给出了扭曲局部BRST对称性和扭曲局部洛伦兹对称性，并证明了作用量和应力张量是BRST精确的。给出了一组BRST不变拓扑算子。还找到了矢量扭曲超对称性和反对称张量扭曲超对称性及其代数。
|
English: Hardware-aware neural architecture designs have been predominantly focusing
on optimizing model performance on single hardware and model development
complexity, where another important factor, model deployment complexity, has
been largely ignored. In this paper, we argue that, for applications that may
be deployed on multiple hardware, having different single-hardware models
across the deployed hardware makes it hard to guarantee consistent outputs
across hardware and duplicates engineering work for debugging and fixing. To
minimize such deployment cost, we propose an alternative solution,
multi-hardware models, where a single architecture is developed for multiple
hardware. With thoughtful search space design and incorporating the proposed
multi-hardware metrics in neural architecture search, we discover
multi-hardware models that give state-of-the-art (SoTA) performance across
multiple hardware in both average and worse case scenarios. For performance on
individual hardware, the single multi-hardware model yields similar or better
results than SoTA performance on accelerators like GPU, DSP and EdgeTPU which
was achieved by different models, while having similar performance with
MobilenetV3 Large Minimalistic model on mobile CPU.
Chinese: 硬件感知的神经架构设计主要集中于优化单硬件上的模型性能和模型开发复杂性，而另一个重要因素——模型部署复杂性——在很大程度上被忽视了。在本文中，我们主张，对于那些可能部署在多个硬件上的应用，在部署的硬件上使用不同的单硬件模型会使跨硬件保证一致输出变得困难，并重复调试和修复的工程工作。为了最小化这种部署成本，我们提出了一种替代方案——多硬件模型，即为多个硬件开发单个架构。通过精心设计的搜索空间和在神经架构搜索中结合我们提出的多硬件指标，我们发现多硬件模型在平均和最坏情况场景下都能在多个硬件上提供最先进（SoTA）的性能。对于单个硬件上的性能，单个多硬件模型产生的结果与不同模型在GPU、DSP和EdgeTPU等加速器上实现的SoTA性能相当或更好，同时在移动CPU上与MobilenetV3 Large Minimalistic模型的性能相似。
|
English: It is well known that building analytical performance models in practice is
difficult because it requires a considerable degree of proficiency in the
underlying mathematics. In this paper, we propose a machine-learning approach
to derive performance models from data. We focus on queuing networks, and
crucially exploit a deterministic approximation of their average dynamics in
terms of a compact system of ordinary differential equations. We encode these
equations into a recurrent neural network whose weights can be directly related
to model parameters. This allows for an interpretable structure of the neural
network, which can be trained from system measurements to yield a white-box
parameterized model that can be used for prediction purposes such as what-if
analyses and capacity planning. Using synthetic models as well as a real case
study of a load-balancing system, we show the effectiveness of our technique in
yielding models with high predictive power.
Chinese: 众所周知，在实践中构建分析性能模型是困难的，因为它需要相当程度的数学基础技能。在本文中，我们提出了一种从数据中推导性能模型的数据学习方法。我们关注排队网络，并关键地利用了它们平均动态的确定性近似，以一个紧凑的常微分方程组表示。我们将这些方程编码到一个循环神经网络中，其权重可以直接与模型参数相关联。这使得神经网络具有可解释的结构，该结构可以从系统测量中训练，以产生一个白盒参数化模型，该模型可用于预测目的，例如假设分析和容量规划。使用合成模型以及一个负载均衡系统的真实案例研究，我们展示了我们的技术在产生具有高预测能力模型方面的有效性。
|
English: The Kepler Spacecraft has discovered a large number of planets up to one-year
periods and down to terrestrial sizes. While the majority of the target stars
are main-sequence dwarfs of spectral type F, G, and K, Kepler covers stars with
effective temperature as low as 2500 K, which corresponds to M stars. These
cooler stars allow characterization of small planets near the habitable zone,
yet it is not clear if this population is representative of that around FGK
stars. In this paper, we calculate the occurrence of planets around stars of
different spectral types as a function of planet radius and distance from the
star, and show that they are significantly different from each other. We
further identify two trends: First, the occurrence of Earth to Neptune-sized
planets is successively higher toward later spectral types at all orbital
periods probed by Kepler; Planets around M stars occur twice as frequently as
around G stars, and thrice as frequently as around F stars. Second, a drop in
planet occurrence is evident at all spectral types inward of a 10 day orbital
period, with a plateau further out. By assigning to each spectral type a median
stellar mass, we show that the distance from the star where this drop occurs is
stellar mass dependent, and scales with semi-major axis as the cube root of
stellar mass. By comparing different mechanisms of planet formation, trapping
and destruction, we find that this scaling best matches the location of the
pre-main-sequence co-rotation radius, indicating efficient trapping of
migrating planets or planetary building blocks. These results demonstrate the
stellar-mass dependence of the planet population, both in terms of occurrence
rate and of orbital distribution. The prominent stellar-mass dependence of the
inner boundary of the planet population shows that the formation or migration
of planets is sensitive to the stellar parameters.
Chinese: 开普勒太空飞船发现了很多周期长达一年、大小与地球相当的行星。虽然目标恒星中多数是光谱类型为F、G和K的主序矮星，但开普勒还覆盖了有效温度低至2500K的恒星，这对应于M型恒星。这些较冷的恒星使得我们能够表征宜居带附近的小行星，但目前尚不清楚这一星系是否代表了围绕F、G、K型恒星周围的行星系。在本文中，我们计算了不同光谱类型恒星周围行星的发生率，并发现它们随着行星半径和距离恒星的变化而显著不同。我们进一步识别出两种趋势：首先，在开普勒探测到的所有轨道周期中，地球到海王星大小的行星发生率随着光谱类型的变晚而依次升高；M型恒星周围的行星发生率是G型恒星的2倍，是F型恒星的3倍。其次，在所有光谱类型中，周期小于10天的行星发生率明显下降，而在更远距离处则趋于平稳。通过为每种光谱类型分配一个中值恒星质量，我们表明行星发生率下降发生的距离与恒星质量相关，并随着半长轴呈恒星质量的三次方根比例变化。通过比较不同的行星形成、捕获和毁灭机制，我们发现这种比例最符合主序前共转半径的位置，表明迁移中的行星或行星建造块被高效捕获。这些结果表明行星群体在发生率和轨道分布方面都依赖于恒星质量。行星群体内边界明显的恒星质量依赖性表明，行星的形成或迁移对恒星参数敏感。
|
English: The violation of Bell inequality not only provides the most radical departure
of quantum theory from classical concepts, but also paves the way of
applications in such as device independent randomness certification. Here, we
derive the tight upper bound of the maximum quantum value for chained Bell
inequality with arbitrary number of measurements on each party. \lxh{ The
constraints where the upper bound saturates are also presented. This method
provides us the necessary and sufficient conditions for some quantum states to
violate the chained Bell inequality with arbitrary number of measurements}.
Based on the tight upper bound we present the lower bounds on the device
independent randomness with respect to the Werner states. \lxh{In particular,
we present lower bounds on the randomness generation rates of chained Bell
inequality for different number of measurements, which are compared with the
family of Bell inequalities proposed by Wooltorton et al. [Phys. Rev. Lett.
129, 150403 (2022)]. Our results show that chained Bell inequality with three
measurements has certain advantages at a low level of noise and could be used
to improve randomness generation rates in practice.
Chinese: 贝尔不等式的违反不仅标志着量子理论从经典概念中彻底分离，而且为诸如设备无关随机性认证等应用领域铺平了道路。在这里，我们推导出链式贝尔不等式在每方任意数量测量下的最大量子值的紧上界。其中，上界饱和的约束条件也被提出。这种方法为我们提供了某些量子状态在任意数量测量下违反链式贝尔不等式的必要且充分条件。基于紧上界，我们提出了关于Werner态的设备无关随机性的下界。特别是，我们针对不同测量数量的链式贝尔不等式随机性生成速率提出了下界，并与Wooltorton等人[物理评论快报129，150403（2022）]提出的贝尔不等式族进行了比较。我们的结果表明，在低噪声水平下，具有三个测量的链式贝尔不等式具有一定的优势，并可用于实际中提高随机性生成速率。
|
English: We build a sample of distant (D > 80 kpc) stellar halo stars with measured
radial velocities. Faint ($20 < g <22$) candidate blue horizontal branch (BHB)
stars were selected using the deep, but wide, multi-epoch Sloan Digital Sky
Survey photometry. Follow-up spectroscopy for these A-type stars was performed
using the VLT-FORS2 instrument. We classify stars according to their Balmer
line profiles, and find 7 are bona fide BHB stars and 31 are blue stragglers
(BS). Owing to the magnitude range of our sample, even the intrinsically
fainter BS stars can reach out to D ~ 90 kpc. We complement this sample of
A-type stars with intrinsically brighter, intermediate-age, asymptotic giant
branch stars. A set of 4 distant cool carbon stars is compiled from the
literature and we perform spectroscopic follow-up on a further 4 N-type carbon
stars using the WHT-ISIS instrument. Altogether, this provides us with the
largest sample to date of individual star tracers out to r ~ 150 kpc. We find
that the radial velocity dispersion of these tracers falls rapidly at large
distances and is surprisingly cold (sigma_r ~ 50-60 km/s) between 100-150 kpc.
Relating the measured radial velocities to the mass of the Milky Way requires
knowledge of the (unknown) tracer density profile and anisotropy at these
distances. Nonetheless, by assuming the stellar halo stars between 50-150 kpc
have a moderate density fall-off (with power-law slope alpha < 5) and are on
radial orbits (sigma^2_t/sigma^2_r < 1), we infer that the mass within 150 kpc
is less than 10^12 M_solar and suggest it probably lies in the range (5-10) x
10^11 M_solar. We discuss the implications of such a low mass for the Milky
Way.
Chinese: 我们构建了一个样本，其中包含具有测量径向速度的遥远（D > 80 kpc）恒星晕星。使用深度但广泛的斯隆数字巡天多epoch光度测量，选择了微弱（20 < g < 22）的候选蓝色水平分支（BHB）星。对这些A型星进行了VLT-FORS2仪器的后续光谱观测。我们根据它们的巴尔末线轮廓对恒星进行分类，发现7颗是真正的BHB星，31颗是蓝色游星（BS）。由于我们样本的亮度范围，即使是本质上较暗的BS星也能延伸到D ~ 90 kpc。我们用本质上亮度更高、中等年龄、渐近巨星分支星补充了这一A型星样本。从文献中汇编了一套4颗遥远的冷却碳星，并使用WHT-ISIS仪器对另外4颗N型碳星进行了光谱后续观测。总的来说，这为我们提供了迄今为止最大的r ~ 150 kpc范围内的单个恒星追踪者样本。我们发现，这些追踪者的径向速度散度在较大距离上迅速下降，并且在100-150 kpc之间出奇地冷（sigma_r ~ 50-60 km/s）。将测量的径向速度与银河系的质量联系起来，需要了解这些距离处的（未知）追踪者密度分布和各向异性。尽管如此，通过假设50-150 kpc之间的恒星晕星具有适度的密度下降（幂律斜率alpha < 5）并且处于径向轨道（sigma^2_t/sigma^2_r < 1），我们推断150 kpc以内的质量小于10^12 M_solar，并建议它可能位于（5-10）x 10^11 M_solar的范围内。我们讨论了这种低质量对银河系的含义。
|
English: The possibility of imposing partially twisted boundary conditions is
investigated for the scalar sector of lattice QCD. According to the commonly
shared belief, the presence of quark-antiquark annihilation diagrams in the
intermediate state generally hinders the use of the partial twisting. Using
effective field theory techniques in a finite volume, and studying the scalar
sector of QCD with total isospin I=1, we however demonstrate that partial
twisting can still be performed, despite the fact that annihilation diagrams
are present. The reason for this are delicate cancellations, which emerge due
to the graded symmetry in partially quenched QCD with valence, sea and ghost
quarks. The modified Luescher equation in case of partial twisting is given.
Chinese: 对于格点量子色动力学（lattice QCD）标量部分的局部扭曲边界条件施加的可能性进行了研究。根据普遍共识，中间态中存在夸克-反夸克湮灭图通常会阻碍局部扭曲的使用。然而，通过在有限体积中使用有效场论技术，并研究总同位旋I=1的QCD标量部分，我们证明了尽管存在湮灭图，局部扭曲仍然可以实施。其原因在于存在精妙的抵消，这些抵消是由于带有价夸克、海夸克和鬼夸克的局部退火QCD中的分级对称性而产生的。给出了局部扭曲情况下的修正Luescher方程。
|
English: We present some cosmological models which unify the late and early-time
acceleration eras with the radiation and the matter domination era, and we
realize the cosmological models by using the theoretical framework of $F(R)$
gravity. Particularly, the first model unifies the late and early-time
acceleration with the matter domination era, and the second model unifies all
the evolution eras of our Universe. The two models are described in the same
way at early and late times, and only the intermediate stages of the evolution
have some differences. Each cosmological model contains two Type IV
singularities which are chosen to occur one at the end of the inflationary era
and one at the end of the matter domination era. The cosmological models at
early times are approximately identical to the $R^2$ inflation model, so these
describe a slow-roll inflationary era which ends when the slow-roll parameters
become of order one. The inflationary era is followed by the radiation era and
after that the matter domination era follows, which lasts until the second Type
IV singularity, and then the late-time acceleration era follows. The models
produce a nearly scale invariant power spectrum of primordial curvature
perturbations and a scalar-to-tensor ratio which are compatible with the most
recent observational data and it seems that the deceleration acceleration
transition is crucially affected by the presence of the second Type IV
singularity which occurs at the end of the matter domination era. We perform an
analysis of the Hubble horizon evolution, and in addition, we investigate which
$F(R)$ gravity can successfully realize each of the four cosmological epochs.
Chinese: 我们提出了一些宇宙学模型，这些模型将晚期和早期加速时代与辐射和物质主导时代统一起来，我们通过使用$F(R)$引力的理论框架来实现这些宇宙学模型。特别是，第一个模型将晚期和早期加速与物质主导时代统一起来，第二个模型统一了我们宇宙的所有演化时代。这两个模型在早期和晚期以相同的方式描述，只是在演化的中间阶段有一些差异。每个宇宙学模型包含两个类型IV奇点，这些奇点被选在膨胀时代的末尾和物质主导时代的末尾发生。早期时间的宇宙学模型与$R^2$膨胀模型近似相同，因此这些描述了一个慢滚膨胀时代，当慢滚参数达到一阶时结束。膨胀时代之后是辐射时代，然后是物质主导时代，它一直持续到第二个类型IV奇点，然后是晚期加速时代。这些模型产生了一个几乎尺度不变的原始曲率扰动功率谱和一个标量到张量比，这些与最新的观测数据相容。似乎减速到加速的过渡过程受到物质主导时代末尾出现的第二个类型IV奇点的关键影响。我们对哈勃视界演化进行了分析，此外，我们还研究了哪种$F(R)$引力可以成功地实现这四个宇宙学时代中的每一个。
|
English: Measuring the polarization of the prompt gamma-ray emission from GRBs can
significantly improve our understanding of both the GRB emission mechanisms, as
well as the underlying engine driving the explosion. We searched for
polarization in the prompt gamma-ray emission of GRB 041219a with the SPI
instrument on INTEGRAL. Using multiple-detector coincidence events in the
100--350 keV energy band, our analysis yields a polarization fraction from this
GRB of 99 +- 33 %. Statistically, we cannot claim a polarization detection from
this source. Moreover, different event selection criteria lead to even less
significant polarization fractions, e.g. lower polarization fractions are
obtained when higher energies are included in the analysis. We cannot strongly
rule out the possibility that the measured modulation is dominated by
instrumental systematics. Therefore, SPI observations of GRB 041219a do not
significantly constrain GRB models. However, this measurement demonstrates the
capability of SPI to measure polarization, and the techniques developed for
this analysis.
Chinese: 测量来自伽玛射线暴（GRBs）的prompt伽玛射线发射的偏振可以显著提高我们对GRB发射机制以及驱动爆炸的底层引擎的理解。我们使用INTEGRAL上的SPI仪器在GRB 041219a的prompt伽玛射线发射中寻找偏振。在100--350 keV能量带中，通过多个探测器巧合事件的分析，我们得到这个GRB的偏振分数为99 ± 33%。从统计学上讲，我们不能从这个源头上断言检测到了偏振。此外，不同的事件选择标准导致偏振分数更加不显著，例如，当分析中包含更高能量时，得到的偏振分数更低。我们不能完全排除所测量的调制主要由仪器系统误差主导的可能性。因此，SPI对GRB 041219a的观测并没有显著约束GRB模型。然而，这一测量证明了SPI测量偏振的能力，以及为这次分析开发的技巧。
|
English: We have analyzed the reaction $\chi_{c0}\to \bar{p} K^+\Lambda$ reported by
the BESIII Collaboration, taking into account the contributions from the
intermediate $K(1830)$, $N(2300)$, and $\Lambda(1520)$ resonances. Our results
are in good agreement with the BESIII measurements, and it is found that the
anomalous enhancement near the $\bar{p}\Lambda$ threshold is mainly due to the
contribution of the $K(1830)$ resonance. We also show that the interference of
the high-mass $N^*$ and $\Lambda^*$ can not produce the anomalous enhancement
near the $\bar{p}\Lambda$ threshold.
Chinese: 我们分析了BESIII合作组报道的反应$\chi_{c0}\to \bar{p} K^+\Lambda$，考虑了中间态$K(1830)$、$N(2300)$和$\Lambda(1520)$共振的贡献。我们的结果与BESIII测量结果吻合良好，并发现$\bar{p}\Lambda$阈附近的反常增强主要归因于$K(1830)$共振的贡献。我们还表明，高能$N^*$和$\Lambda^*$的干涉不能产生$\bar{p}\Lambda$阈附近的反常增强。
|
English: Safety is the main concern in the aviation industry, where even minor
operational issues can lead to serious consequences. This study addresses the
need for comprehensive aviation accident analysis by leveraging natural
language processing (NLP) and advanced AI models to classify the phase of
flight from unstructured aviation accident analysis narratives. The research
aims to determine whether the phase of flight can be inferred from narratives
of post-accident events using NLP techniques. The classification performance of
various deep learning models was evaluated. For single RNN-based models, LSTM
achieved an accuracy of 63%, precision 60%, and recall 61%. BiLSTM recorded an
accuracy of 64%, precision 63%, and a recall of 64%. GRU exhibited balanced
performance with an accuracy and recall of 60% and a precision of 63%. Joint
RNN-based models further enhanced predictive capabilities. GRU-LSTM,
LSTM-BiLSTM, and GRU-BiLSTM demonstrated accuracy rates of 62%, 67%, and 60%,
respectively, showcasing the benefits of combining these architectures. To
provide a comprehensive overview of model performance, single and combined
models were compared in terms of the various metrics. These results underscore
the models' capacity to classify the phase of flight from raw text narratives,
equipping aviation industry stakeholders with valuable insights for proactive
decision-making. Therefore, this research signifies a substantial advancement
in the application of NLP and deep learning models to enhance aviation safety.
Chinese: 航空业的主要关注点是安全，即使轻微的操作问题也可能导致严重后果。本研究通过利用自然语言处理（NLP）和先进的AI模型，从非结构化的航空事故分析叙述中分类飞行阶段，以解决全面航空事故分析的需求。研究旨在确定是否可以使用NLP技术从事故后事件叙述中推断飞行阶段。评估了各种深度学习模型的分类性能。对于基于单个RNN的模型，LSTM达到了63%的准确率、60%的精确率和61%的召回率。BiLSTM记录了64%的准确率、63%的精确率和64%的召回率。GRU表现出均衡的性能，准确率和召回率均为60%，精确率为63%。基于联合RNN的模型进一步增强了预测能力。GRU-LSTM、LSTM-BiLSTM和GRU-BiLSTM分别展示了62%、67%和60%的准确率，展示了结合这些架构的优势。为了全面概述模型性能，将单个和组合模型在各项指标上进行了比较。这些结果突出了模型从原始文本叙述中分类飞行阶段的能力，为航空业利益相关者提供了主动决策的宝贵见解。因此，这项研究标志着NLP和深度学习模型在提升航空安全应用方面取得了重大进展。
|
English: Quantitative susceptibility mapping (QSM) is a powerful MRI technique that
has shown great potential in quantifying tissue susceptibility in numerous
neurological disorders. However, the intrinsic ill-posed dipole inversion
problem greatly affects the accuracy of the susceptibility map. We propose
QSMGAN: a 3D deep convolutional neural network approach based on a 3D U-Net
architecture with increased receptive field of the input phase compared to the
output and further refined the network using the WGAN with gradient penalty
training strategy. Our method generates accurate QSM maps from single
orientation phase maps efficiently and performs significantly better than
traditional non-learning-based dipole inversion algorithms. The generalization
capability was verified by applying the algorithm to an unseen pathology--brain
tumor patients with radiation-induced cerebral microbleeds.
Chinese: 定量磁化率映射（QSM）是一种强大的核磁共振成像（MRI）技术，在定量多种神经系统疾病的组织磁化率方面显示出巨大潜力。然而，固有的非适定偶极反演问题极大地影响了磁化率图的准确性。我们提出了QSMGAN：一种基于3D U-Net架构的3D深度卷积神经网络方法，其输入相位相比输出具有更大的感受野，并进一步使用带梯度惩罚的WGAN训练策略对网络进行优化。我们的方法能够高效地从单方向相位图生成精确的QSM图，性能显著优于传统的非学习型偶极反演算法。通过将算法应用于未见过病理——放疗后脑微出血的脑肿瘤患者——验证了其泛化能力。
|
English: Bayesian regression remains a simple but effective tool based on Bayesian
inference techniques. For large-scale applications, with complicated posterior
distributions, Markov Chain Monte Carlo methods are applied. To improve the
well-known computational burden of Markov Chain Monte Carlo approach for
Bayesian regression, we developed a multilevel Gibbs sampler for Bayesian
regression of linear mixed models. The level hierarchy of data matrices is
created by clustering the features and/or samples of data matrices.
Additionally, the use of correlated samples is investigated for variance
reduction to improve the convergence of the Markov Chain. Testing on a diverse
set of data sets, speed-up is achieved for almost all of them without
significant loss in predictive performance.
Chinese: 贝叶斯回归仍然是一种基于贝叶斯推理技术的简单但有效的工具。对于大规模应用，当后验分布复杂时，应用马尔可夫链蒙特卡洛方法。为了改善贝叶斯回归中马尔可夫链蒙特卡洛方法众所周知的高计算负担，我们为线性混合模型的贝叶斯回归开发了一种多级吉布斯抽样器。通过聚类数据矩阵的特征和/或样本，创建了数据矩阵的层级结构。此外，为了减少方差并提高马尔可夫链的收敛性，研究了使用相关样本的方法。在多个数据集上进行测试，几乎所有数据集都实现了加速，同时没有显著损失预测性能。
|
English: The growth and structural analysis of topological semimetal (TSM) PdTe2 were
carried out in this study. The self-flux method was employed to grow the single
crystals which were structurally characterized by XRD, SEM and EDAX, while the
vibrational modes were observed by Raman spectroscopy. Further, the transport
properties of the grown crystal are also investigated, which show the presence
of the weak anti-localization effect. The low field (1Tesla)
magnetoconductivity is studied by Hikami-Larkin-Nagaoka (HLN) model, and the
physical parameters are extracted. Further, a quadratic term and a linear term
in applied field were added in HLN model, which are accounted for quantum and
classical contributions in conduction mechanism. The modified HLN model was
used to study magneto-conductivity in entire field range and at temperature
from 2-100 K. This study not only confirmed the growth of single crystal PdTe2,
but also verified the presence of topological surface states (TSS) through the
HLN analysis of magneto-transport measurements.
Chinese: 本研究对拓扑半金属（TSM）PdTe2的生长和结构分析进行了研究。采用自流法生长单晶，并通过XRD、SEM和EDAX对其结构进行了表征，同时通过拉曼光谱观察了振动模式。此外，还对生长晶体的传输特性进行了研究，结果显示存在弱反局域化效应。低场（1特斯拉）磁阻率通过Hikami-Larkin-Nagaoka（HLN）模型进行了研究，并提取了物理参数。进一步地，在HLN模型中添加了应用场中的二次项和一次项，以考虑传导机制中的量子效应和经典贡献。修改后的HLN模型用于研究整个磁场范围和2-100 K温度下的磁阻率。这项研究不仅证实了PdTe2单晶的生长，而且通过HLN分析磁传输测量结果验证了拓扑表面态（TSS）的存在。
|
English: We consider a stochastic control problem which is composed of a controlled
stochastic differential equation, and whose associated cost functional is
defined through a controlled backward stochastic differential equation. Under
appropriate convexity assumptions on the coefficients of the forward and the
backward equations we prove the existence of an optimal control on a suitable
reference stochastic system. The proof is based on an approximation of the
stochastic control problem by a sequence of control problems with smooth
coefficients, admitting an optimal feedback control. The quadruplet formed by
this optimal feedback control and the associated solution of the forward and
the backward equations is shown to converge in law, at least along a
subsequence. The convexity assumptions on the coefficients then allow to
construct from this limit an admissible control process which, on an
appropriate reference stochastic system, is optimal for our stochastic control
problem.
Chinese: 我们考虑一个由受控随机微分方程组成的随机控制问题，其相关的成本泛函通过受控的反向随机微分方程定义。在关于正向和反向方程系数的适当凸性假设下，我们证明了在合适的参考随机系统上存在最优控制。证明基于通过一系列具有光滑系数的控制问题对随机控制问题的近似，这些控制问题允许最优反馈控制。由这个最优反馈控制和与正向及反向方程相关联的解组成的四元组被证明在至少一个子序列上按分布收敛。然后，系数的凸性假设允许从这个极限构建一个可接受的控制过程，在适当的参考随机系统上，对于我们的随机控制问题，这个控制过程是最优的。
|
English: We determine upper and lower bounds on the zero forcing number of 2-connected
outerplanar graphs in terms of the structure of the weak dual. We show that the
upper bound is always at most half the number of vertices of the graph. This
work generalizes work of Hern\'andez, Ranilla and Ranilla-Cortina who proved a
similar result for maximal outerplanar graphs.
Chinese: 我们根据弱对偶的结构，确定了2连通外平面图的零强制数的上下界。我们证明该上界始终不超过图中顶点数的一半。这项工作推广了Hern\'andez、Ranilla和Ranilla-Cortina的研究成果，他们曾对极大外平面图证明了类似的结果。
|
English: Let $F$ (over $\mathbb{Q}$) be a totally real number field of narrow class
number $1$. We generalize a result of Kohnen on the determination of half
integral weight modular forms by their Fourier coefficients supported on
squarefree (algebraic) integers. We also give a soft proof that infinitely many
Fourier coefficients supported on squarefree integers are non-vanishing.
Chinese: 设 $F$（在 $\mathbb{Q}$ 上）为一个狭义类数 $1$ 的完全实数域。我们推广了Kohnen关于通过其支持在平方自由（代数）整数上的傅里叶系数来确定半整数权模形式的结果。我们还给出一个软证明，即无限多个支持在平方自由整数上的傅里叶系数不为零。
|
English: Resonance-mediated many body decays of heavy mesons are analyzed. We focus on
some particular processes, in which the available phase space for the decay of
the intermediate resonance is very narrow. It is shown that the mass selection
criteria used in several experimental studies of D and B meson decays could
lead to a significant underestimation of branching ratios.
Chinese: 共振介导的重介子多体衰变被分析。我们关注一些特定的过程，在这些过程中，中间共振衰变的可用相空间非常狭窄。研究表明，在几个D介子和B介子衰变的实验研究中使用的质量选择标准可能导致分支比被显著低估。
|
English: We show that the delay between GRB170817A and GW170817 is incompatible with
de-beamed emission from an off-axis relativistic jet. The prompt emission and
the subsequent radio and X-ray observations can instead be interpreted within a
giant-flare-like scenario, being the result of a relativistic outflow driven by
the ultra-strong magnetic field produced by magnetohydrodynamic amplification
during the merger of the progenitor double neutron-star binary. Within such
picture, the data indicate that the outflow must be endowed with a steep
velocity profile, with a relatively fast tail extending to Gamma~8. Since the
conditions for the launch of such an outflow are quite general, and the
presence of a velocity profile is a natural expectation of the acceleration
process, most neutron star binary mergers should feature this quasi-isotropic,
hard X-ray emission component, that can be a powerful guide to the discovery of
additional kilonovae associated to relatively nearby gravitational wave events.
Chinese: 我们表明，GRB170817A与GW170817之间的延迟与来自非轴线相对论射流的去束流发射是不相容的。快速发射以及随后的无线电和X射线观测可以通过类似巨大耀斑的情景来解释，这是由双中子星前体双星合并期间磁流体动力学放大产生的超强磁场驱动的相对论性喷流的结果。在这种图景下，数据表明喷流必须具有陡峭的速度分布，有一个相对较快的尾部延伸到伽马~8。由于这种喷流的发射条件相当普遍，并且速度分布是加速过程的自然预期，大多数中子星双星合并应该具有这种准各向同性的硬X射线发射成分，这可以成为发现与相对较近的引力波事件相关的额外千新星的有力指南。
|
English: Expansion dynamics at the yoctosecond timescale affect the evolution of the
quark gluon plasma (QGP) created in heavy ion collisions. We show how these
dynamics are accessible through Hanbury Brown and Twiss (HBT) intensity
interferometry of direct photons emitted from the interior of the QGP. A
detector placed close to the beam axis is particularly sensitive to early polar
momentum anisotropies of the QGP. Observing a modification of the HBT signal at
the proposed FoCal detector of the LHC ALICE experiment would allow to measure
the isotropization time of the plasma and could provide first experimental
evidence for photon double pulses at the yoctosecond timescale.
Chinese: 皮秒时间尺度上的扩张动力学影响了在重离子碰撞中产生的夸克胶子等离子体（QGP）的演化。我们展示了如何通过直接从QGP内部发射的光子的汉弗莱布朗和蒂斯（HBT）强度干涉测量来访问这些动力学。靠近束轴放置的探测器特别对QGP的早期极化动量各向异性敏感。在提议的FoCal探测器的LHC ALICE实验中观察HBT信号的修改将允许测量等离子体的各向同化时间，并可能提供光子双脉冲在皮秒时间尺度上的首次实验证据。
|
English: Essential to various practical applications of lithium-ion batteries is the
availability of accurate equivalent circuit models. This paper presents a new
coupled electro-thermal model for batteries and studies how to extract it from
data. We consider the problem of maximum likelihood parameter estimation,
which, however, is nontrivial to solve as the model is nonlinear in both its
dynamics and measurement. We propose to leverage the Bayesian optimization
approach, owing to its machine learning-driven capability in handling complex
optimization problems and searching for global optima. To enhance the parameter
search efficiency, we dynamically narrow and refine the search space in
Bayesian optimization. The proposed system identification approach can
efficiently determine the parameters of the coupled electro-thermal model. It
is amenable to practical implementation, with few requirements on the
experiment, data types, and optimization setups, and well applicable to many
other battery models.
Chinese: 锂离子电池在众多实用应用中，准确等效电路模型的存在至关重要。本文提出了一种新的电池耦合电热模型，并研究了如何从数据中提取该模型。我们考虑了最大似然参数估计的问题，然而，由于模型在动力学和测量上都是非线性的，这个问题解决起来并不简单。我们提出利用贝叶斯优化方法，因为它在处理复杂优化问题和寻找全局最优解方面具有机器学习驱动的能力。为了提高参数搜索效率，我们在贝叶斯优化中动态地缩小和细化搜索空间。所提出的系统识别方法可以有效地确定耦合电热模型的参数。该方法易于实际应用，对实验、数据类型和优化设置的要求很少，并且适用于许多其他电池模型。
|
English: We investigate the $\gamma$-ray and X-ray properties of the flat spectrum
radio quasar (FSRQ) \4c50 at redshift $z= 1.517$. The {\it Fermi} Large Area
Telescope (LAT) data indicate that this source was in an active state since
2013 July. During the active period, the $\gamma$-ray flux increased by more
than a factor of three and two distinct flares were detected with the
variability timescale as short as several hours.
The $\gamma$-ray spectra can be well fitted by a log-parabola. From the
fitting, we find a correlation between the peak energy and spectral curvature
for the $\gamma$-ray spectra, which is the first time seen in $\gamma$-ray
emission from a blazar. The {\it Swift} X-ray Telescope (XRT) data show that
the source was variable at X-ray energies, but no evidence shows flux or
spectral changes related to the $\gamma$-ray activity. The broad-band X-ray
spectrum obtained with {\it Swift} XRT and {\it NuSTAR} is well described by a
broken PL model, with an extremely hard spectrum ($\Gamma_{1} \sim 0.1$) below
the break energy, $E_{\rm break} \sim 2.1 {\rm keV}$, and $\Gamma_{2} \sim 1.5$
above the break energy. The spectral steepening below $\sim 3$ keV is likely
due to the low energy cut-off in the energy distribution of the photon-emitting
electron population. Both the $\gamma$-ray and X-ray emission appear harder
when brighter. The broad-band spectral energy distribution (SED) is constructed
for the source, and we provide a model fit to the SED. Our modeling suggests
that the emission region should be outside the broad line region, and the
properties of the region indicate a jet with 42\% of the Eddington power during
the active state.
Chinese: 我们研究了红移 $z= 1.517$ 的平坦谱射电类星体（FSRQ）4c50的伽马射线和X射线特性。{\it Fermi} 大面积望远镜（LAT）的数据表明，该源自2013年7月以来一直处于活跃状态。在活跃期间，伽马射线通量增加了超过三个数量级，并检测到两次明显的爆发，其变化时间尺度短至数小时。伽马射线光谱可以用对数抛物线很好地拟合。从拟合中，我们发现伽马射线光谱的峰值能量与光谱曲率之间存在相关性，这是在来自喷流星系的伽马射线发射中首次观察到。{\it Swift} X射线望远镜（XRT）的数据显示，该源在X射线能量上是可变的，但没有证据表明通量或光谱变化与伽马射线活动有关。使用{\it Swift} XRT和{\it NuSTAR}获得的宽带X射线光谱可以用一个断开的双幂律模型很好地描述，其中在断开能量$E_{\rm break} \sim 2.1 {\rm keV}$以下有一个非常硬的谱（$\Gamma_{1} \sim 0.1$），在断开能量以上$\Gamma_{2} \sim 1.5$。在$\sim 3$ keV以下的谱变陡可能是由于光子发射电子能谱中的低能截止。伽马射线和X射线发射在亮度增加时看起来更硬。我们为该源构建了宽带光谱能量分布（SED），并提供了对SED的模型拟合。我们的建模表明，发射区域应在宽带线区之外，该区域的特性表明在活跃状态下有一个具有42%爱丁顿功率的喷流。
|
English: Non-Gaussian operations are essential to exploit the quantum advantages in
optical continuous variable quantum information protocols. We focus on
mode-selective photon addition and subtraction as experimentally promising
processes to create multimode non-Gaussian states. Our approach is based on
correlation functions, as is common in quantum statistical mechanics and
condensed matter physics, mixed with quantum optics tools. We formulate an
analytical expression of the Wigner function after subtraction or addition of a
single photon, for arbitrarily many modes. It is used to demonstrate
entanglement properties specific to non-Gaussian states, and also leads to a
practical and elegant condition for Wigner function negativity. Finally, we
analyse the potential of photon addition and subtraction for an experimentally
generated multimode Gaussian state.
Chinese: 非高斯操作对于利用光学连续变量量子信息协议中的量子优势至关重要。我们专注于模式选择的光子添加和减去，作为实验上具有前景的过程来创建多模非高斯态。我们的方法基于相关函数，这在量子统计力学和凝聚态物理学中很常见，并结合了量子光学工具。我们为任意多个模式在减去或添加单个光子后，给出了Wigner函数的解析表达式。它被用来展示非高斯态特有的纠缠性质，并导致Wigner函数负性的实用且优雅的条件。最后，我们分析了光子添加和减去对于实验生成多模高斯态的潜力。
|
English: Emerging at the end of 2019, COVID-19 has become a public health threat to
people worldwide. Apart from the deaths who tested positive for COVID-19, many
others have died from causes indirectly related to COVID-19. Therefore, the
COVID-19 confirmed deaths underestimate the influence of the pandemic on the
society; instead, the measure of `excess deaths' is a more objective and
comparable way to assess the scale of the epidemic and formulate lessons. One
common practical issue in analyzing the impact of COVID-19 is to determine the
`pre-COVID-19' period and the `post-COVID-19' period. We apply a change point
detection method to identify any change points using the excess deaths in
Belgium.
Chinese: 新兴于2019年末的COVID-19已成为全球公共卫生威胁。除了检测出COVID-19呈阳性的死亡病例外，还有许多人因与COVID-19间接相关的原因而死亡。因此，COVID-19的确诊死亡人数低估了该流行病对社会的影响；相反，使用“超额死亡”作为衡量指标是一种更为客观和可比的方式，以评估疫情的规模并总结教训。在分析COVID-19影响时的一个常见实际问题是确定“疫情前”时期和“疫情后”时期。我们应用变化点检测方法，利用比利时的超额死亡数据来识别任何变化点。
|
English: In this Letter we comment on one particular aspect of Hypatia's enigmatic
biography by translating into English a short poem that appeared in a recent
review of the third revised Polish edition of Maria Dzielska's book about
Hypatia. It poses a simple and specifc question: did Hypatia know about the
negative numbers?
Chinese: 在本文中，我们通过翻译一首最近出现在Maria Dzielska所著希帕蒂亚传记第三版修订波兰版评论中的短诗，评论了希帕蒂亚神秘传记的一个特定方面。它提出了一个简单而具体的问题：希帕蒂亚是否了解负数？
|
English: The Q- state Potts model on the Bethe lattice is investigated for Q<2. The
magnetization of this model exhibits a complicated behavior including both the
period doubling bifurcation and chaos. The Lyapunov exponents of the
Potts-Bethe map are considered as order parameters. We find a scaling behavior
in the distribution of Lyapunov exponents in fully developed chaotic case.
Using the thermodynamic formalism of dynamical systems have we investigated the
nonanalytic behavior in the distribution of Lyapunov exponents and located the
point of phase transition of the ''chaotic free energy''.
Chinese: 在Bethe格子上对Q<2的Q态Potts模型进行了研究。该模型的磁化表现出复杂的行为，包括周期加倍分岔和混沌。将Potts-Bethe图的Lyapunov指数视为序参量。我们在充分发展的混沌情况下发现Lyapunov指数的分布具有标度行为。利用动力系统的热力学形式，我们研究了Lyapunov指数分布中的非解析行为，并定位了“混沌自由能”相变的点。
|
English: The performance of medical image classification has been enhanced by deep
convolutional neural networks (CNNs), which are typically trained with
cross-entropy (CE) loss. However, when the label presents an intrinsic ordinal
property in nature, e.g., the development from benign to malignant tumor, CE
loss cannot take into account such ordinal information to allow for better
generalization. To improve model generalization with ordinal information, we
propose a novel meta ordinal regression forest (MORF) method for medical image
classification with ordinal labels, which learns the ordinal relationship
through the combination of convolutional neural network and differential forest
in a meta-learning framework. The merits of the proposed MORF come from the
following two components: a tree-wise weighting net (TWW-Net) and a grouped
feature selection (GFS) module. First, the TWW-Net assigns each tree in the
forest with a specific weight that is mapped from the classification loss of
the corresponding tree. Hence, all the trees possess varying weights, which is
helpful for alleviating the tree-wise prediction variance. Second, the GFS
module enables a dynamic forest rather than a fixed one that was previously
used, allowing for random feature perturbation. During training, we
alternatively optimize the parameters of the CNN backbone and TWW-Net in the
meta-learning framework through calculating the Hessian matrix. Experimental
results on two medical image classification datasets with ordinal labels, i.e.,
LIDC-IDRI and Breast Ultrasound Dataset, demonstrate the superior performances
of our MORF method over existing state-of-the-art methods.
Chinese: 深度卷积神经网络（CNN）提升了医学图像分类的性能，通常使用交叉熵（CE）损失进行训练。然而，当标签在自然中呈现固有的序数属性时，例如从良性到恶性的肿瘤发展，CE损失无法考虑这种序数信息以实现更好的泛化。为了利用序数信息提升模型泛化能力，我们提出了一种新的序数回归森林（MORF）方法，用于具有序数标签的医学图像分类，该方法通过元学习框架中卷积神经网络和差分森林的组合来学习序数关系。所提出的MORF方法的优点来自以下两个组件：树形权重网络（TWW-Net）和分组特征选择（GFS）模块。首先，TWW-Net为森林中的每棵树分配一个特定权重，该权重从对应树的分类损失映射而来。因此，所有树都拥有不同的权重，这有助于缓解树形预测方差。其次，GFS模块使森林动态化而非固定化，允许随机特征扰动。在训练过程中，我们通过计算Hessian矩阵，在元学习框架中交替优化CNN主干网络和TWW-Net的参数。在两个具有序数标签的医学图像分类数据集（即LIDC-IDRI和乳腺超声数据集）上的实验结果表明，我们的MORF方法优于现有最先进方法。
|
English: Consider the full primitive equations, i.e. the three dimensional primitive
equations coupled to the equation for temperature and salinity, and subject to
outer forces. It is shown that this set of equations is globally strongly
well-posed for arbitrary large initial data lying in certain interpolation
spaces, which are explicitly characterized as subspaces of $H^{2/p,p}$,
$1<p<\infty$, satisfying certain boundary conditions. In particular, global
well-posedeness of the full primitive equations is obtained for initial data
having less differentiability properties than $H^1$, hereby generalizing by
result by Cao and Titi (Ann. of Math. (2) 166 (2007), no. 1, 245-267) to the
case of non-smooth data. In addition, it is shown that the solutions are
exponentially decaying provided the outer forces possess this property.
Chinese: 考虑完整的原始方程，即三维原始方程与温度和盐度方程耦合，并受到外部力的影响。证明了这套方程对于任意大的初始数据在某些明确表征为$H^{2/p,p}$，$1<p<\infty$的子空间中，满足某些边界条件的情况下，是全局强可解的。特别是，对于初始数据具有比$H^1$更少的光滑性属性，这将Cao和Titi的结果（《数学年刊》(2) 166 (2007)，第1期，第245-267页）推广到了非光滑数据的情况。此外，还证明了如果外部力具有这种性质，则解将呈指数衰减。
|
English: The halo dark matter (DM) can be gravitationally captured by the Sun. For
self-interacting DM (SIDM), we show that the number of DM trapped inside the
Sun remains unsuppressed even if the DM-nucleon cross section is negligible. We
consider a SIDM model where $U(1)$ gauge symmetry is introduced to account for
the DM self-interaction. Such a model naturally leads to isospin violation for
DM-nucleon interaction, although isospin symmetry is still allowed as a special
case. We show that the detection of neutrino signature from DM annihilation in
the Sun can probe those SIDM parameter ranges not reachable by direct
detections. Those parameter ranges are either the region with a very small
$m_{\chi}$ or the region opened up due to isospin violations.
Chinese: 球状暗物质（DM）可以被太阳引力捕获。对于自相互作用暗物质（SIDM），我们表明即使DM-核子截面可以忽略不计，太阳内部捕获的DM数量也不会受到抑制。我们考虑了一个SIDM模型，在该模型中引入了$U(1)$规范对称性来解释DM的自相互作用。这样的模型自然会导致DM-核子相互作用的同位旋违反，尽管在特定情况下同位旋对称性仍然允许。我们表明，太阳中DM湮灭产生的中微子签名的探测可以探索直接探测无法触及的SIDM参数范围。这些参数范围要么是DM质量非常小的区域，要么是由于同位旋违反而开放的区域。
|
English: We give a version of Noether theorem adapted to the framework of
mu-symmetries; this extends to such case recent work by Muriel, Romero and
Olver in the framework of lambda-symmetries, and connects mu-symmetries of a
Lagrangian to a suitably modified conservation law. In some cases this
"mu-conservation law'' actually reduces to a standard one; we also note a
relation between mu-symmetries and conditional invariants. We also consider the
case where the variational principle is itself formulated as requiring
vanishing variation under mu-prolonged variation fields, leading to modified
Euler-Lagrange equations. In this setting mu-symmetries of the Lagrangian
correspond to standard conservation laws as in the standard Noether theorem. We
finally propose some applications and examples.
Chinese: 我们给出了一种适用于mu对称性框架的诺特定理版本；这扩展了Muriel、Romero和Olver在lambda对称性框架下最近的工作，并将拉格朗日函数的mu对称性与一个适当修改的守恒定律联系起来。在某些情况下，这个“mu守恒定律”实际上简化为一个标准守恒定律；我们还注意到mu对称性与条件不变量之间的关系。我们还考虑了变分原理本身被表述为在mu延拓的变分场下要求变分为零的情况，这导致了修改后的欧拉-拉格朗日方程。在这种情况下，拉格朗日的mu对称性对应于标准守恒定律，正如标准诺特定理中那样。最后，我们提出了一些应用和例子。
|
English: We present the observation of the \Heebar nucleus, the heaviest antinucleus
observed to date. In total, 18 \Heebar counts were detected at the STAR
experiment at RHIC in 10$^{9}$ recorded Au+Au collisions at beam energies of
$\sqrt{s_{NN}}$ = 200 GeV and 62 GeV. The background has been estimated, and
the misidentification probability is found to be lower than 10$^{-11}$.
Chinese: 我们报告了对最重的反核素 \Heebar 核的观测。在RHIC的STAR实验中，总共检测到了18个 \Heebar 计数，这些计数是在10^9次记录的Au+Au碰撞中发现的，碰撞能量分别为 $\sqrt{s_{NN}}$ = 200 GeV 和 62 GeV。背景已经被估计，误识别概率被发现低于10^-11。
|
English: We present ELSA, a practical solution for creating deep networks that can
easily be deployed at different levels of sparsity. The core idea is to embed
one or more sparse networks within a single dense network as a proper subset of
the weights. At prediction time, any sparse model can be extracted effortlessly
simply be zeroing out weights according to a predefined mask. ELSA is simple,
powerful and highly flexible. It can use essentially any existing technique for
network sparsification and network training. In particular, it does not
restrict the loss function, architecture or the optimization technique. Our
experiments show that ELSA's advantages of flexible deployment comes with no or
just a negligible reduction in prediction quality compared to the standard way
of using multiple sparse networks that are trained and stored independently.
Chinese: 我们提出ELSA，一种实用的解决方案，用于创建深度网络，这些网络可以轻松地部署在稀疏性的不同层次。核心思想是将一个或多个稀疏网络嵌入到一个单一密集网络中，作为权重的适当子集。在预测时，只需根据预定义的掩码简单地将权重设为零，就可以毫不费力地提取任何稀疏模型。ELSA既简单又强大，并且非常灵活。它可以使用任何现有的网络稀疏化和网络训练技术。特别是，它不限制损失函数、架构或优化技术。我们的实验表明，ELSA在灵活部署方面的优势不会导致预测质量与标准方式相比有任何或几乎可以忽略的下降，即使用多个独立训练和存储的稀疏网络。
|
English: The action principle is used to derive, by an entirely algebraic approach,
gauge transformations of the full vacuum-to-vacuum transition amplitude
(generating functional) from the Coulomb gauge to arbitrary covariant gauges
and in turn to the celebrated Fock-Schwinger (FS) gauge for the abelian (QED)
gauge theory without recourse to path integrals or to commutation rules and
without making use of delta functionals. The interest in the FS gauge, in
particular, is that it leads to Faddeev-Popov ghosts-free non-abelian gauge
theories. This method is expected to be applicable to non-abelian gauge
theories including supersymmetric ones.
Chinese: 作用量原理被用于通过完全代数方法推导从库仑规范到任意协变规范，进而到阿贝尔（QED）规范理论中著名的Fock-Schwinger（FS）规范的全真空到真空跃迁振幅（生成泛函）的规范变换，而无需借助路径积分或对易规则，也不使用δ泛函。FS规范特别引人注目之处在于它导致了Faddeev-Popov无鬼泛函的非阿贝尔规范理论。预计该方法适用于包括超对称在内的非阿贝尔规范理论。
|
English: Positron sources are critical components of the future linear collider
projects. This is essentially due to the high luminosity required, orders of
magnitude higher than existing ones. In addition, polarization of the positron
beam rather expands the physics research potential of the machine. In this
framework, the Compton sources for polarized positron production are taken into
account where the high energy gamma rays are produced by the Compton scattering
and subsequently converted into the polarized electron-positron pairs in a
target-converter. The Compton multiple Interaction Point (IP) line is proposed
as one of the solutions to increase the number of the positrons produced. The
gamma ray production with the Compton multiple IP line is simulated and used
for polarized positron generation. Later, a capture section based on an
adiabatic matching device (AMD) followed by a pre-injector linac is simulated
to capture and accelerate the positron beam.
Chinese: 正电子源是未来直线对撞机项目的关键组件。这主要是因为需要极高的亮度，比现有的亮度高好几个数量级。此外，正电子束的极化也极大地扩展了机器的物理研究潜力。在这个框架下，考虑了用于极化正电子产生的康普顿源，其中高能伽马射线通过康普顿散射产生，随后在靶-转换器中转化为极化的电子-正电子对。提出康普顿多重相互作用点（IP）线作为增加产生正电子数量的解决方案之一。使用康普顿多重IP线产生的伽马射线进行模拟，并用于极化正电子的产生。随后，模拟了一个基于绝热匹配装置（AMD）的捕获段，随后是一个预注入直线加速器，用于捕获和加速正电子束。
|
English: Let $X$ be a smooth Fano variety over $\mathbb{C}$ and let $B$ be a smooth
projective curve over $\mathbb{C}$. Geometric Manin's Conjecture predicts the
structure of the irreducible components $M \subset \mathrm{Mor}(B, X)$
parametrizing curves which are non-free and have large anticanonical degree.
Following ideas of our previous work, we prove the first prediction of
Geometric Manin's Conjecture describing such irreducible components. As an
application, we prove that there is a proper closed subset $V \subset X$ such
that all non-dominant components of $\mathrm{Mor}(B, X)$ parametrize curves in
$V$, verifying an expectation put forward by Victor Batyrev. We also
demonstrate two important ways that studying $\mathrm{Mor}(B,X)$ differs from
studying the space of sections of a Fano fibration $\mathcal{X} \to B$.
Chinese: 设$X$为$\mathbb{C}$上的光滑Fano簇，$B$为$\mathbb{C}$上的光滑投影曲线。几何Manin猜想预测了非自由且具有大反极性度的曲线$M \subset \mathrm{Mor}(B, X)$的不可约成分的结构。遵循我们之前工作的想法，我们证明了几何Manin猜想的第一个预测，描述了这样的不可约成分。作为一个应用，我们证明了存在$X$的一个闭子集$V \subset X$，使得$\mathrm{Mor}(B, X)$的所有非主导成分均对应于$V$中的曲线，验证了Victor Batyrev提出的期望。我们还展示了研究$\mathrm{Mor}(B,X)$与研究Fano纤维化$\mathcal{X} \to B$的纤维部分的截面的空间的不同之处的两种重要方式。
|
English: Evolution strategy (ES) is one of promising classes of algorithms for
black-box continuous optimization. Despite its broad successes in applications,
theoretical analysis on the speed of its convergence is limited on convex
quadratic functions and their monotonic transformation. In this study, an upper
bound and a lower bound of the rate of linear convergence of the (1+1)-ES on
locally $L$-strongly convex functions with $U$-Lipschitz continuous gradient
are derived as $\exp\left(-\Omega_{d\to\infty}\left(\frac{L}{d\cdot
U}\right)\right)$ and $\exp\left(-\frac1d\right)$, respectively. Notably, any
prior knowledge on the mathematical properties of the objective function such
as Lipschitz constant is not given to the algorithm, whereas the existing
analyses of derivative-free optimization algorithms require them.
Chinese: 进化策略（ES）是用于黑盒连续优化的有前景的算法类别之一。尽管它在应用中取得了广泛的成功，但其收敛速度的理论分析在凸二次函数及其单调变换方面仍然有限。在本研究中，我们推导了(1+1)-ES在具有$U$-Lipschitz连续梯度的局部$L$-强凸函数上的线性收敛速度的上界和下界，分别为$\exp\left(-\Omega_{d\to\infty}\left(\frac{L}{d\cdot U}\right)\right)$和$\exp\left(-\frac1d\right)$。值得注意的是，算法没有给出关于目标函数数学性质（如Lipschitz常数）的任何先验知识，而现有的无导数优化算法的分析则要求提供这些知识。
|
English: We analyze the quantum phase transition for a set of $N$-two level systems
interacting with a bosonic mode in the adiabatic regime. Through the
Born-Oppenheimer approximation, we obtain the finite-size scaling expansion for
many physical observables and, in particular, for the entanglement content of
the system.
Chinese: 我们分析了在绝热极限下与玻色模式相互作用的 N 个双能级系统的量子相变。通过玻恩-奥本海默近似，我们得到了许多物理可观测量和特别地是系统纠缠含量的有限尺寸标度展开。
|
English: We construct unique local solutions for the spherically-symmetric
Einstein-Klein-Gordon-AdS system subject to a large class of initial and
boundary conditions including some considered in the context of the AdS-CFT
correspondence. The proof relies on estimates developed for the linear wave
equation by the second author and involves a careful renormalization of the
dynamical variables, including a renormalization of the well-known Hawking
mass. For some of the boundary conditions considered this system is expected to
exhibit rich global dynamics, including the existence of hairy black holes. The
present paper furnishes a starting point for such global investigations.
Chinese: 我们针对球对称的Einstein-Klein-Gordon-AdS系统，在包括AdS-CFT对应中考虑的一些初始和边界条件的大类条件下，构建了唯一的局部解。该证明依赖于第二作者为线性波动方程发展的估计，并涉及对动力学变量的仔细重整化，包括对著名的霍金质量的重整化。对于考虑的一些边界条件，该系统预计将表现出丰富的全局动力学，包括毛发黑洞的存在。本文为这类全局研究提供了起点。
|
English: It is generally accepted that phonons in a superfluid Bose gas are Goldstone
bosons. This is justified by spontaneous symmetry breaking (SSB), which is
usually defined as follows: the Hamiltonian of the system is invariant under
the $U(1)$ transformation $\hat{\Psi}(\mathbf{r},t)\rightarrow e^{i\alpha}%
\hat{\Psi}(\mathbf{r},t)$, whereas the order parameter $\Psi(\mathbf{r},t)$ is
not. However, the strict definition of SSB is different: the Hamiltonian and
the boundary conditions are invariant under a symmetry transformation, while
the \emph{ground state} is not. Based on the latter criterion, we study a
finite system of spinless, weakly interacting bosons using three approaches:
the standard Bogoliubov method, the particle-number-conserving Bogoliubov
method, and the approach based on the exact ground-state wave function. Our
results show that the answer to the question in the title is \textquotedblleft
no\textquotedblright. Thus, phonons in a real-world (finite) superfluid Bose
gas are similar to sound in a classical gas: they are not Goldstone bosons, but
quantised collective vibrational modes arising from the interaction between
atoms. In the case of an infinite Bose gas, however, the picture becomes
paradoxical: the ground state can be regarded as either infinitely degenerate
or non-degenerate, making the phonon both similar to a Goldstone boson and
different from it.
Chinese: 人们普遍认为超流体玻色气体中的声子是Goldstone玻色子。这一点通过自发对称性破缺（SSB）得到了证实，SSB通常被定义为如下：系统的哈密顿量在$U(1)$变换$\hat{\Psi}(\mathbf{r},t)\rightarrow e^{i\alpha}\hat{\Psi}(\mathbf{r},t)$下是不变的，而序参数$\Psi(\mathbf{r},t)$则不是。然而，SSB的严格定义是不同的：哈密顿量和边界条件在对称变换下是不变的，而基态则不是。基于后者这一标准，我们使用三种方法研究了无自旋、弱相互作用的玻色子有限系统：标准Bogoliubov方法、粒子数守恒的Bogoliubov方法和基于精确基态波函数的方法。我们的结果表明，标题中的问题的答案是“不”。因此，现实世界（有限）超流体玻色气体中的声子类似于经典气体中的声音：它们不是Goldstone玻色子，而是由原子间相互作用产生的量子化集体振动模式。然而，在无限玻色气体的情况下，情况变得矛盾：基态可以被视为无限简并或非简并，使得声子既类似于Goldstone玻色子，又与之不同。
|
English: The resonant external field-assisted Breit-Wheeler process (Oleinik
resonances) for strong electromagnetic fields with intensities less than the
critical Schwinger field has been theoretically studied. The resonant
kinematics has been studied in detail. The case of high-energy initial gamma
quanta and emerging ultrarelativistic electron-positron pairs is studied. The
resonant differential cross section is obtained. The generation of narrow beams
of ultrarelativistic positrons (for Channel A) and electrons (for Channel B) is
predicted with a probability significantly exceeding corresponding to the
non-resonant process.
Chinese: 对强度低于临界Schwinger场的强电磁场中的共振外部场辅助Breit-Wheeler过程（Oleinik共振）进行了理论研究。详细研究了共振动力学。研究了高能初始伽马光子和产生的超相对论性电子-正电子对的情况。得到了共振微分截面。预测了超相对论性正电子（通道A）和电子（通道B）窄束的产生，其概率显著高于非共振过程。
|
English: We present the first primary transit light curve of the hot Jupiter HAT-P-16b
in the near-UV photometric band. We observed this object on December 29,2012 in
order to update the transit ephemeris, constrain its planetary parameters and
search for magnetic field interference. Vidotto et al. (2011a) postulate that
the magnetic field of HAT-P-16b can be constrained if its near-UV light curve
shows an early ingress compared to its optical light curve, while its egress
remains unchanged. However, we did not detect an early ingress in our night of
observing when using a cadence of 60 seconds and an average photometric
precision of 2.26mmag. We find a near-UV planetary radius of
Rp=1.274+-0.057RJup which is consistent with its near-IR radius of
Rp=1.289+-0.066RJup (Buchhave et al., 2010). We developed an automated
reduction pipeline and modeling package to process our data. The data reduction
package synthesizes a set of IRAF scripts to calibrate images and perform
aperture photometry. The modeling package utilizes the Levenberg-Marquardt
minimization algorithm to find a least-squares best fit and a differential
evolution Markov Chain Monte Carlo algorithm to find the best fit to the light
curve. To constrain the red noise in both fitting models we use the residual
permutation (rosary bead) method and time-averaging method.
Chinese: 我们展示了热木星HAT-P-16b在近紫外波段的第一次主凌光曲线。我们在2012年12月29日观测了该天体，以更新过境历元，限制其行星参数，并搜索磁场干扰。Vidotto等人（2011a）假设，如果HAT-P-16b的近紫外光曲线显示出比其光学光曲线更早的主凌，而其主凌结束保持不变，那么可以约束该行星的磁场。然而，在我们观测的夜晚，我们没有检测到比预期更早的主凌，当时我们使用了每秒60次的采样率，平均光子精度为2.26毫mag。我们找到了近紫外行星半径为Rp=1.274±0.057RJup，这与Buchhave等人（2010）发现的近红外半径Rp=1.289±0.066RJup一致。我们开发了一套自动化的数据处理流水线和建模包来处理我们的数据。数据处理包合成了一系列IRAF脚本，用于校准图像和执行光圈光子测量。建模包利用Levenberg-Marquardt最小化算法来寻找最小二乘最佳拟合，以及微分进化马尔可夫链蒙特卡罗算法来寻找光曲线的最佳拟合。为了限制两个拟合模型中的红色噪声，我们使用了残差排列（玫瑰珠）方法和时间平均方法。
|
English: In the last two decades, several classes of codes are introduced to protect
the copyrighted digital data. They have important applications in the scenarios
like digital fingerprinting and broadcast encryption schemes. In this paper we
will discuss three important classes of such codes, namely, frameproof codes,
parent-identifying codes and traceability codes.
Firstly, suppose $N(t)$ is the minimal integer such that there exists a
binary $t$-frameproof code of length $N$ with cardinality larger than $N$, we
prove that $N(t)\ge\frac{15+\sqrt{33}}{24} (t-2)^2$, which is a great
improvement of the previously known bound $N(t)\ge\binom{t+1}{2}$. Moreover, we
find that the determination of $N(t)$ is closely related to a conjecture of
Erd\H{o}s, Frankl and F\"uredi posed in the 1980's, which implies the
conjectured value $N(t)=t^2+o(t^2)$. Secondly, we derive a new upper bound for
parent-identifying codes, which is superior than all previously known bounds.
Thirdly, we present an upper bound for 3-traceability codes, which shows that a
$q$-ary 3-traceability code of length $N$ can have at most $cq^{\lceil
N/9\rceil}$ codewords, where $c$ is a constant only related to the code length
$N$. It is the first meaningful upper bound for 3-traceability codes and our
result supports a conjecture of Blackburn et al. posed in 2010.
Chinese: 在过去二十年里，引入了几种代码类别来保护版权数字数据。它们在数字指纹和广播加密方案等场景中有着重要的应用。在本文中，我们将讨论三种重要的此类代码类别，即帧证明代码、父识别代码和可追溯代码。
首先，假设$N(t)$是满足存在一个长度为$N$的、基数大于$N$的二进制$t$-帧证明代码的最小整数，我们证明$N(t)\ge\frac{15+\sqrt{33}}{24} (t-2)^2$，这是对之前已知界限$N(t)\ge\binom{t+1}{2}$的极大改进。此外，我们发现$N(t)$的确定与Erdős、Frankl和Füredi在20世纪80年代提出的猜想密切相关，该猜想暗示了猜想值$N(t)=t^2+o(t^2)$。其次，我们推导出父识别代码的新上界，该上界优于所有之前已知的界限。第三，我们提出了3-可追溯代码的上界，这表明长度为$N$的$q$进制3-可追溯代码最多可以有$cq^{\lceil N/9\rceil}$个码字，其中$c$是一个仅与代码长度$N$相关的常数。这是3-可追溯代码的第一个有意义的上界，我们的结果支持Blackburn等人于2010年提出的猜想。
|
English: The quality of user experience online is affected by the relevance and
placement of advertisements. We propose a new system for selecting and
displaying visual advertisements in image search result sets. Our method
compares the visual similarity of candidate ads to the image search results and
selects the most visually similar ad to be displayed. The method further
selects an appropriate location in the displayed image grid to minimize the
perceptual visual differences between the ad and its neighbors. We conduct an
experiment with about 900 users and find that our proposed method provides
significant improvement in the users' overall satisfaction with the image
search experience, without diminishing the users' ability to see the ad or
recall the advertised brand.
Chinese: 在线用户体验受广告的相关性和排放位置影响。我们提出一种用于图像搜索结果集中选择和展示视觉广告的新系统。我们的方法比较候选广告与图像搜索结果的视觉相似度，并选择最相似的广告进行展示。该方法进一步选择合适的展示位置，以最小化广告与其相邻元素之间的感知视觉差异。我们进行了约900名用户的实验，发现我们提出的方法显著提升了用户对图像搜索体验的整体满意度，同时未降低用户观看广告或回忆广告品牌的能力。
|
English: We present a calculation of the finite volume corrections to meson masses and
decay constants in three flavour Partially Quenched Chiral Perturbation Theory
(PQChPT) through two-loop order in the chiral expansion for the flavour-charged
(or off-diagonal) pseudoscalar mesons. The analytical results are obtained for
three sea quark flavours with one, two or three different masses. We reproduce
the known infinite volume results and the finite volume results in the
unquenched case. The calculation has been performed using the supersymmetric
formulation of PQChPT as well as with a quark-flow technique.
Partial analytical results can be found in the appendices. Some examples of
cases relevant to lattice QCD are studied numerically. Numerical programs for
all results are available as part of the CHIRON package.
Chinese: 我们通过在味道-电荷（或非对角）伪标量介子的手征展开中到二阶循环计算，提出了在三种味道部分淬火手征扰动理论（PQChPT）中，介子质量及其衰变常数的有限体积修正的计算。对于具有一个、两个或三个不同质量的三个海夸克味道，我们得到了解析结果。我们重现了已知的无限体积结果和未淬火情况下的有限体积结果。该计算使用了PQChPT的超对称形式以及夸克流技术。部分解析结果可以在附录中找到。一些与格点QCD相关的情况的例子被数值研究。所有结果的数值程序作为CHIRON软件包的一部分提供。
|
English: We investigate the potential sources of theoretical systematics in the
anisotropic Baryon Acoustic Oscillation (BAO) distance scale measurements from
the clustering of galaxies in configuration space using the final Data Release
(DR12) of the Baryon Oscillation Spectroscopic Survey (BOSS). We perform a
detailed study of the impact on BAO measurements from choices in the
methodology such as fiducial cosmology, clustering estimators, random
catalogues, fitting templates, and covariance matrices.
The theoretical systematic uncertainties in BAO parameters are found to be
0.002 in the isotropic dilation $\alpha$ and 0.003 in the quadrupolar dilation
$\epsilon$. The leading source of systematic uncertainty is related to the
reconstruction techniques. Theoretical uncertainties are sub-dominant compared
with the statistical uncertainties for BOSS survey, accounting
$0.2\sigma_{stat}$ for $\alpha$ and $0.25\sigma_{stat}$ for $\epsilon$
($\sigma_{\alpha,stat} \sim$0.010 and $\sigma_{\epsilon,stat}\sim$ 0.012
respectively). We also present BAO-only distance scale constraints from the
anisotropic analysis of the correlation function. Our constraints on the
angular diameter distance $D_A(z)$ and the Hubble parameter $H(z)$, including
both statistical and theoretical systematic uncertainties, are 1.5\% and 2.8\%
at $z_{\rm eff}=0.38$, 1.4\% and 2.4\% at $z_{\rm eff}=0.51$, and 1.7\% and
2.6\% at $z_{\rm eff}=0.61$. This paper is part of a set that analyzes the
final galaxy clustering dataset from BOSS. The measurements and likelihoods
presented here are cross-checked with other BAO analysis in \citet{Acacia16}.
The systematic error budget concerning the methodology on post-reconstruction
BAO analysis presented here is used in \citet{Acacia16} to produce the final
cosmological constraints from BOSS.
Chinese: 我们使用重子振荡光谱巡天（BOSS）的最终数据发布（DR12），研究了各向异性重子声波振荡（BAO）距离尺测量中的理论系统误差来源，该方法基于配置空间中星系团聚类分析。我们对选择中的方法论（如基准宇宙学、聚类估计器、随机目录、拟合模板和协方差矩阵）对BAO测量产生的影响进行了详细研究。
研究发现，BAO参数中的理论系统不确定性在各向同性膨胀系数α中为0.002，在四极膨胀系数ε中为0.003。系统不确定性的主要来源与重建技术相关。对于BOSS巡天而言，理论不确定性相对于统计不确定性是次要的，分别占α的0.2σ_stat和ε的0.25σ_stat（σ_α,stat约0.010，σ_ε,stat约0.012）。
我们还从相关函数的各向异性分析中提出了仅基于BAO的距离尺约束。在z_eff=0.38、z_eff=0.51和z_eff=0.61时，我们关于角直径距离D_A(z)和哈勃参数H(z)的约束（包括统计和理论系统不确定性）分别为1.5%和2.8%、1.4%和2.4%、1.7%和2.6%。本文是分析BOSS最终星系聚类数据集的一组研究的一部分。本文提出的测量值和似然函数与其他文献\citet{Acacia16}中的BAO分析进行了交叉验证。本文提出的关于后重建BAO分析方法学的系统误差预算被\citet{Acacia16}用于生成BOSS的最终宇宙学约束。
|
English: The field of few-shot learning has recently seen substantial advancements.
Most of these advancements came from casting few-shot learning as a
meta-learning problem. Model Agnostic Meta Learning or MAML is currently one of
the best approaches for few-shot learning via meta-learning. MAML is simple,
elegant and very powerful, however, it has a variety of issues, such as being
very sensitive to neural network architectures, often leading to instability
during training, requiring arduous hyperparameter searches to stabilize
training and achieve high generalization and being very computationally
expensive at both training and inference times. In this paper, we propose
various modifications to MAML that not only stabilize the system, but also
substantially improve the generalization performance, convergence speed and
computational overhead of MAML, which we call MAML++.
Chinese: 少样本学习领域近期取得了重大进展。
这些进展大多源于将少样本学习视为一个元学习问题。
免模型元学习（MAML）是目前通过元学习实现少样本学习的最佳方法之一。
MAML简单、优雅且非常强大，但它存在各种问题，如对神经网络架构非常敏感，
常导致训练过程中的不稳定性，需要艰苦的超参数搜索才能稳定训练并实现高泛化能力，
同时在训练和推理时都计算成本很高。
在本文中，我们提出了对MAML的各种改进，
这些改进不仅稳定了系统，还显著提高了MAML的泛化性能、收敛速度和计算开销，
我们称之为MAML++。
|
English: Condensation phenomena in particle systems typically occur as one of two
distinct types: either as a spontaneous symmetry breaking in a homogeneous
system, in which particle interactions enforce condensation in a randomly
located site, or as an explicit symmetry breaking in a system with background
disorder, in which particles condensate in the site of extremal disorder. In
this paper we confirm a recent conjecture by Godr\`eche and Luck by showing,
for a zero range process with weak site disorder, that there exists a phase
where condensation occurs with an intermediate type of symmetry-breaking, in
which particles condensate in a site randomly chosen from a range of sites
favoured by disorder. We show that this type of condensation is characterised
by the occurrence of a Gamma distribution in the law of the disorder at the
condensation site. We further investigate fluctuations of the condensate size
and confirm a phase diagram, again conjectured by Godr\`eche and Luck, showing
the existence of phases with normal and anomalous fluctuations.
Chinese: 粒子系统中的凝结现象通常以两种不同的类型之一出现：要么是在均匀系统中自发对称破缺，其中粒子相互作用在随机位置强制凝结；要么是在具有背景无序的系统中的显式对称破缺，其中粒子在极端无序的位置凝结。在这篇论文中，我们通过展示对于具有弱位置无序的零范围过程，存在一个相，其中以中间类型的对称破缺发生凝结，粒子在由无序所偏好的位置范围内随机选择的位置凝结。我们表明，这种类型的凝结以凝结位置的无序律中出现伽马分布为特征。我们进一步研究了凝结大小的涨落，并证实了一个相图，这是Godr\`eche和Luck所猜测的，显示了存在具有正常和异常涨落的相。
|
English: Causal DAGs (also known as Bayesian networks) are a popular tool for encoding
conditional dependencies between random variables. In a causal DAG, the random
variables are modeled as vertices in the DAG, and it is stipulated that every
random variable is independent of its ancestors conditioned on its parents. It
is possible, however, for two different causal DAGs on the same set of random
variables to encode exactly the same set of conditional dependencies. Such
causal DAGs are said to be Markov equivalent, and equivalence classes of Markov
equivalent DAGs are known as Markov Equivalent Classes (MECs). Beautiful
combinatorial characterizations of MECs have been developed in the past few
decades, and it is known, in particular that all DAGs in the same MEC must have
the same "skeleton" (underlying undirected graph) and v-structures (induced
subgraph of the form $a\rightarrow b \leftarrow c$).
These combinatorial characterizations also suggest several natural
algorithmic questions. One of these is: given an undirected graph $G$ as input,
how many distinct Markov equivalence classes have the skeleton $G$? Much work
has been devoted in the last few years to this and other closely related
problems. However, to the best of our knowledge, a polynomial time algorithm
for the problem remains unknown.
In this paper, we make progress towards this goal by giving a fixed parameter
tractable algorithm for the above problem, with the parameters being the
treewidth and the maximum degree of the input graph $G$. The main technical
ingredient in our work is a construction we refer to as shadow, which lets us
create a "local description" of long-range constraints imposed by the
combinatorial characterizations of MECs.
Chinese: 因果有向无环图（也称为贝叶斯网络）是编码随机变量之间条件依赖关系的常用工具。在有向无环图中，随机变量被建模为图的顶点，并且规定每个随机变量在给定其父节点的情况下与其祖先独立。然而，对于同一组随机变量上的两个不同的因果有向无环图，可能编码完全相同的条件依赖关系。这样的因果有向无环图被称为马尔可夫等价，马尔可夫等价有向无环图的等价类被称为马尔可夫等价类（MECs）。在过去几十年中，已经发展出MECs优美的组合学特征，并且已知特别是同一MEC中的所有有向无环图必须具有相同的“骨架”（底层无向图）和v结构（形式为$a\rightarrow b \leftarrow c$的导出子图）。
这些组合学特征还提出了几个自然的算法问题。其中之一是：给定一个无向图$G$作为输入，有多少个不同的马尔可夫等价类具有骨架$G$？在过去的几年里，许多工作都致力于这个问题和其他密切相关的问题。然而，据我们所知，这个问题仍然没有多项式时间算法。
在本文中，我们通过给出一个固定参数可解的算法来推进这一目标，参数为输入图$G$的树宽和最大度数。我们工作中的主要技术成分是一个我们称为阴影的结构，它让我们能够创建由MECs的组合学特征强加的长程约束的“局部描述”。
|
English: The effect of the global rotation of the universe on the formation of
galaxies is investigated. It is found that the global rotation provides a
natural origin for the rotation of galaxies, and the morphology of the objects
formed from gravitational instability in a rotating and expanding universe
depends on the amplitude of the density fluctuation, different values of the
amplitude of the fluctuation lead to the formation of elliptical galaxies,
spiral galaxies, and walls. The global rotation gives a natural explanation of
the empirical relation between the angular momentum and mass of galaxies:
$J\propto M^{5/3}$. The present angular velocity of the universe is estimated,
which is $\sim 10^{-13} rad yr^{-1}$.
Chinese: 研究了宇宙整体旋转对星系形成的影响。研究发现，整体旋转为星系旋转提供了自然起源，在旋转和膨胀的宇宙中由引力不稳定性形成的物体的形态取决于密度涨落的振幅，不同的涨落振幅值会导致椭圆星系、旋涡星系和墙的形成。整体旋转为星系角动量与质量之间的经验关系$J\propto M^{5/3}$提供了自然解释。估计了宇宙当前的角速度，约为$10^{-13} rad yr^{-1}$。
|
English: With a scalar potential and a bivector potential, the vector field associated
with the drift of a diffusion is decomposed into a generalized gradient field,
a field perpendicular to the gradient, and a divergence-free field. We give
such decomposition a probabilistic interpretation by introducing cycle velocity
from a bivectorial formalism of nonequilibrium thermodynamics. New
understandings on the mean rates of thermodynamic quantities are presented.
Deterministic dynamical system is further proven to admit a generalized
gradient form with the emerged potential as the Lyapunov function by the method
of random perturbations.
Chinese: 利用标量势和双矢量势，与扩散漂移相关的矢量场被分解为一个广义梯度场、一个垂直于梯度的场以及一个无散度场。我们通过引入来自非平衡热力学双矢量公式的循环速度，对此分解给出了概率解释。我们提出了关于热力学量平均速率的新理解。通过随机扰动法，进一步证明了确定性动力系统可以接受一个广义梯度形式，其中出现的势作为李雅普诺夫函数。
|
English: Cloud computing is bringing a revolution in computing environment replacing
traditional software installations, licensing issues into complete on-demand
services through internet. Microsoft office 365 a cloud based office
application is available to clients online hence no need to buy and install the
software. On Facebook a social networking website, users upload videos which
uses cloud provider's storage service so less hardware cost for
clients.Virtualization technology has great contribution in advent of cloud
computing. Paper describes implementation of Private Cloud using open source
operating system Ubuntu 10.04 server edition, installation of Ubuntu Enterprise
Cloud with Eucalyptus 1.6.2 and providing CentOS 5.3 operating system through
cloud.
Chinese: 云计算正在引发计算环境的一场革命，用互联网上的完全按需服务取代了传统的软件安装，解决了许可问题。基于云的Microsoft Office 365办公软件可以通过网络访问，因此无需购买和安装软件。在Facebook这一社交网络网站上，用户上传的视频使用云服务提供商的存储服务，因此减少了对客户的硬件成本。虚拟化技术在云计算的兴起中有着巨大的贡献。本文描述了使用开源操作系统Ubuntu 10.04服务器版实现私有云的实施，安装了Ubuntu Enterprise Cloud with Eucalyptus 1.6.2，并通过云提供CentOS 5.3操作系统。
|
English: Markov decision processes (MDPs) are a well studied framework for solving
sequential decision making problems under uncertainty. Exact methods for
solving MDPs based on dynamic programming such as policy iteration and value
iteration are effective on small problems. In problems with a large discrete
state space or with continuous state spaces, a compact representation is
essential for providing an efficient approximation solutions to MDPs. Commonly
used approximation algorithms involving constructing basis functions for
projecting the value function onto a low dimensional subspace, and building a
factored or hierarchical graphical model to decompose the transition and reward
functions. However, hand-coding a good compact representation for a given
reinforcement learning (RL) task can be quite difficult and time consuming.
Recent approaches have attempted to automatically discover efficient
representations for RL.
In this thesis proposal, we discuss the problems of automatically
constructing structured kernel for kernel based RL, a popular approach to
learning non-parametric approximations for value function. We explore a space
of kernel structures which are built compositionally from base kernels using a
context-free grammar. We examine a greedy algorithm for searching over the
structure space. To demonstrate how the learned structure can represent and
approximate the original RL problem in terms of compactness and efficiency, we
plan to evaluate our method on a synthetic problem and compare it to other RL
baselines.
Chinese: 马尔可夫决策过程（MDPs）是一个在不确定性下解决序列决策问题的广泛研究的框架。基于动态规划的精确方法，如策略迭代和值迭代，在小型问题上非常有效。在具有大型离散状态空间或连续状态空间的问题中，提供高效近似解的紧凑表示至关重要。常用的近似算法涉及构建基函数以将值函数投影到低维子空间，以及构建分解转移和奖励函数的因子化或层次化图形模型。然而，为给定的强化学习（RL）任务手动编码一个良好的紧凑表示可能相当困难且耗时。近期的研究尝试自动发现RL的有效表示。
在本论文提案中，我们讨论了自动构建基于核的强化学习的结构化核的问题，这是一种流行的学习非参数值函数近似的方法。我们探索了一个由上下文无关文法构建的核结构空间，其中基本核是组合性的。我们研究了一个在结构空间中搜索的贪心算法。为了展示所学到的结构如何以紧凑性和效率为标准表示和近似原始RL问题，我们计划在一个合成问题上评估我们的方法，并与其他的RL基准进行比较。
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.