Positron Emission Tomography Lung Image Respiratory Motion Correcting with Equivariant Transformer

In addressing the challenge of motion artifacts in Positron Emission Tomography (PET) lung scans, our studyintroduces the Triple Equivariant Motion Transformer (TEMT), an innovative, unsupervised, deep-learningbasedframework for efficient respiratory motion correction in PET imaging. Unlike traditional techniques,which segment PET data into bins throughout a respiratory cycle and often face issues such as inefficiency andoveremphasis on certain artifacts, TEMT employs Convolutional Neural Networks (CNNs) for effective featureextraction and motion decomposition.TEMT’s unique approach involves transforming motion sequences into Liegroup domains to highlight fundamental motion patterns, coupled with employing competitive weighting forprecise target deformation field generation. Our empirical evaluations confirm TEMT’s superior performancein handling diverse PET lung datasets compared to existing image registration networks. Experimental resultsdemonstrate that TEMT achieved Dice indices of 91.40%, 85.41%, 79.78%, and 72.16% on simulated geometricphantom data, lung voxel phantom data, cardiopulmonary voxel phantom data, and clinical data, respectively. Tofacilitate further research and practical application, the TEMT framework, along with its implementation detailsand part of the simulation data, is made publicly accessible at https://github.com/yehaowei/temt.

Lie symmetry group transformation for MHD natural convection flow of nanofluid over linearly porous stretching sheet in presence of thermal stratification

The magnetohydrodynamics （MHD） convection flow and heat transfer of an incompressible viscous nanofluid past a semi-infinite vertical stretching sheet in the pres- ence of thermal stratification are examined. The partial differential equations governing the problem under consideration are transformed by a special form of the Lie symmetry group transformations, i.e., a one-parameter group of transformations into a system of ordinary differential equations which are numerically solved using the Runge-Kutta-Gill- based shooting method. It is concluded that the flow field, temperature, and nanoparticle volume fraction profiles are significantly influenced by the thermal stratification and the magnetic field.

THE UNIFORMLY BOUNDEDNESS OF THE RIESZ TRANSFORMS ON THE CAYLEY HEISENBERG GROUPS

In this article,the authors estimate some functions by using the explicit expression of the heat kernels for the Cayley Heisenberg groups,and then prove the uniform boundedness of the Riesz transforms on these nilpotent Lie groups.

Lie point symmetry algebras and finite transformation groups of the general Broer-Kaup system

Using a new symmetry group theory, the transformation groups and symmetries of the general Broer-Kaup system are obtained. The results are much simpler than those obtained via the standard approaches.

ALMOST PERIODICITY AND EQUICONTINUITY OF THE TOPOLOGICAL TRANSFORMATION GROUP

In this paper, a characterization of almost periodicity of topological transformation groups on uniform spaces is given. By searching the appropriate base for uniform structure, it is shown that the topological transformation group is topologically equivalent to an isometric one if it is uniformly equicontinuous.

Hardy Type Estimates for Riesz Transforms Associated with Schrdinger Operators on the Heisenberg Group

Abstract. Let H^n be the Heisenberg group and Q = 2n＋2 be its homogeneous dimen- sion. In this paper, we consider the Schr6dinger operator -△H^n ＋V, where △H^n is the sub-Laplacian and V is the nonnegative potential belonging to the reverse H61der class Bql for ql _〉 Q/2. We show that the operators T1 = V（-△H^n-In ＋V）-1 and T2 = V1/2（-△H^n-V）-1/2 are both bounded from 1 n HL^1（H^n ） into L1（H^n）. Our results are also valid on the stratified Lie group.

Finite symmetry transformation group and localized structures of the (2+1)-dimensional coupled Burgers equation

In this paper, the finite symmetry transformation group of the （2＋1）-dimensional coupled Burgers equation is studied by the modified direct method, and with the help of the truncated Painleve′ expansion approach, some special localized structures for the （2＋1）-dimensional coupled Burgers equation are obtained, in particular, the dromion-like and solitoff-like structures.

On the Group of Units for the Ring of Linear Transformations

In this paper, we introduce a practical method for obtaining the structure of thegroup of units for the ring of linear transformations of a vector space over an arbitrary field,and we give a further generalization of the result in [3].

WAVELET TRANSFORM ASSOCIATED TO THE AFFINE GROUP AGS,

This paper considers wavelet transforms associated to the affine group, which is more general than the paper given by R. Murenzi, and it seems more important in mathematical theory and more natural to be used to analyze signals in more than 1-dimension.

APPLICATION OF ONE-PARAMETER GROUPS OF TRANSFORMATION IN MECHANICS

In this paper,including some partial differential equations with a number of independent variables, which can he reduced by the infinitesimal form of the group, we obtain the theory of similarity transformation and its application of the second order nonlinear partial differential equations which have two independent variables and two dependent variables in mechanics.

Wind turbine clutter mitigation using morphological component analysis with group sparsity

To address the problem that dynamic wind turbine clutter(WTC)significantly degrades the performance of weather radar,a WTC mitigation algorithm using morphological component analysis(MCA)with group sparsity is studied in this paper.The ground clutter is suppressed firstly to reduce the morphological compositions of radar echo.After that,the MCA algorithm is applied and the window used in the short-time Fourier transform(STFT)is optimized to lessen the spectrum leakage of WTC.Finally,the group sparsity structure of WTC in the STFT domain can be utilized to decrease the degrees of freedom in the solution,thus contributing to better estimation performance of weather signals.The effectiveness and feasibility of the proposed method are demonstrated by numerical simulations.

A GROUP REPRESENTATION OF CANONICAL TRANSFORMATION

The mutual relationships between four generating functions F-1(q, Q), F-2(q, P), F-3(p, P), F-4(p, Q) and four kinds of canonical variables q, p, Q, P concerned in Hamilton's canonical transformations, can be got with linear transformations from seven basic formulae. All of them are Legendre's transformation, which are implemented by 32 matrices of 8 x 8 which are homomorphic to D-4 point group of 8 elements with correspondence of 4:1. Transformations and relationships of four state functions G(P, T), H(P, S), U(V, S), F(V, T) and four variables P, V, T, S in thermodynamics, are just the same Lagendre's transformations with the relationships of canonical transformations. The state functions of thermodynamics are summarily founded on experimental results of macroscope measurements, and Hamilton's canonical transformations are theoretical generalization of classical mechanics. Both group represents are the same, and it is to say, their mathematical frames are the same. This generality indicates the thermodynamical transformation is an example of one-dimensional Hamilton's canonical transformation.

基于数智化视角的企业集团智慧型司库建设探究

随着数字经济的快速发展,企业集团需要加快数智化转型,作为集团运营管理重要载体的司库也需要相应转型。为满足司库数智化转型的三个基本要求。首先,需从司库的操作运营层、资源管控层、决策分析层等三个层级着手创新设计司库数智化转型的功能架构。其次,为支撑该功能架构,需从先进性、集成性、安全性、可拓展性等四个方面着手创新设计司库数智化转型的技术机构。最后,为确保建成智慧型司库,需从机制健全、过程管控、标准优化、数据治理等四个关键环节发力提供坚强保障举措。

企业数字化转型促进了资本跨区域流动吗——基于异地并购视角的研究

加快资本跨区域流动对构建以国内大循环为主体、国内国际双循环相互促进的新发展格局具有重要的战略意义。本文以2008—2022年中国A股上市公司为样本,借助异地并购这一重要的资本跨区域流动形式,考察新发展格局下企业数字化转型对资本跨区域流动的影响。研究发现:企业数字化转型通过降低并购交易成本和提高集团管控能力,有效地促进了异地并购决策,尤其对跨省并购决策的促进作用更显著。异质性分析结果表明,当并购企业所在地区市场化程度更高、税负水平更低、数字金融发展水平更高以及目标企业所在地区营商环境更好时,企业数字化转型对异地并购决策的促进作用更强;同时,这一促进作用在民营企业、非高新技术企业以及高管具有金融背景或海外背景的企业中更显著。本研究丰富了数字经济时代资本跨区域流动驱动因素的研究,从异地并购视角提供了企业数字化转型促进资本跨区域流动的微观证据。

数字化转型、同群效应与企业风险承担

本文基于数字化浪潮下我国企业风险承担意愿不足的现实背景下,从治理能力提升效应、战略韧性增强效应以及环境不确定性对冲效应三个方面阐释了企业数字化转型影响风险承担水平的作用机理,并从行业和地区两个维度论证了企业数字化转型同群效应现象的存在性及其对企业风险承担水平的外生影响。利用2011—2021年我国A股上市公司面板数据,系统考察了企业数字化转型与企业风险承担之间的关系。研究发现:数字化转型显著提高了企业风险承担水平。作用机制方面,企业数字化转型通过对冲外部环境不确定性、提高企业治理能力以及增强企业战略韧性共同提升了企业风险承担水平。进一步研究发现,我国企业数字化转型行为存在明显的行业同群和地区同群特征且是风险承担水平提升的重要原因,同群效应使得高数字化程度企业群体中存在低风险承担水平企业的比例相对较低。即高数字化与低数字化企业风险承担水平分布呈现了明显的“左截尾”特征。

制造业科技自主创新的微观机制考察——河钢集团案例

以河钢集团为例,通过对企业具体实践的详细考察,总结企业推动科技创新的微观机制,可以为有效支持企业科技创新、加快建设国家创新体系、推动我国高质量发展提供参考。在钢铁行业供求失衡矛盾凸显的形势下,河钢集团逐步压减传统钢铁产品产能,培育以自主创新为基础的竞争优势,主动寻求经营理念变革、管理模式创新、产品结构转型与生产技术升级,走出一条钢铁企业的创新发展道路。基于河钢集团的案例考察可以发现,科技创新是一项复杂的系统工程,对于企业而言,科技创新既不能完全依靠政府的支持政策,也不能仅是局限于产品与技术创新,而是需要从经营理念到管理模式,再到产品与技术,进行全方位变革。

陕西省老字号餐饮企业数字化转型发展路径研究

随着数字技术的不断发展,将老字号餐饮企业的发展与数字化转型相融合成为其做大做强的切入口。老字号餐饮企业是展现陕西省历史文化传承的重要组成部分,从陕西省老字号餐饮企业的发展现状来看,老字号餐饮企业数量少,且有减少趋势,经营产品种类较为单一,缺乏创新,老字号餐饮企业正加大数字化转型力度,迎合时代发展需要。陕西省老字号餐饮企业有必要进行数字化转型,扩大经营范围,拓展消费群体,促进产品种类的创新,提高消费者的满意度。为进一步促进陕西省老字号餐饮企业实现数字化转型,政府应加大对老字号餐饮企业的商业保护,为其提供政策扶持。企业应积极丰富产品线,拓展餐饮研学、文化体验、草坪经济、露营经济、线上线下外卖等创新领域,加快数字化转型。同时,企业应通过注册短视频平台账号等加强对外宣传,做好宣传管理工作。

高职数控技术专业群数字化转型

论述了高职数控技术专业群数字化转型的内涵特性、课程体系重构策略和实践探索、专业群数字化转型的实现路径,以便推动高职数控技术专业群的数字化转型进程,提高人才培养质量和竞争力,为其他专业的数字化转型提供参考。

有机农业采纳会促进农户增收吗?——基于新疆枣农的实证分析

有机农业采纳能否促进农户增收,是促进有机农业推广和推动中国农业绿色发展的关键。文中基于新疆地区451份枣农的实地调查数据,采用内生转换回归模型实证检验有机农业采纳对农户的增收效应及其作用机制,并进一步采用分组回归探究了有机农业采纳对农户增收效应的异质性。结果表明:1)有机农业采纳能够显著增加枣农的收入,已采纳有机农业枣农若放弃采纳,其收入下降48.65%;未采纳有机农业枣农若采纳,其收入提高53.57%。2)有机农业采纳对枣农的增收效应存在明显的异质性,采纳有机农业对于来自国家有机产品示范创建区、参与契约农业、文化程度较高和种植规模较大枣农的增收效应更明显。为此,可通过有机红枣产业发展促进农户增收,考虑采纳有机农业对不同枣农增收效应的异质性,政府可鼓励枣农通过土地流转等方式扩大有机红枣种植规模,提高枣农契约农业参与率,加大有机产品认证示范区的创建力度,改善有机农业采纳对枣农的增收效应。

融入上下文特征提取的非自回归神经机器翻译

非自回归翻译(NAT)模型是一种消除目标句子中的顺序依赖关系的翻译模型,在推理速度上取得了显著的突破。然而该模型在翻译质量方面存在一些局限,为探究原因,主要对注意机制进行了细致而全面的初步研究,研究结果揭示了NAT模型在捕捉局部性特征方面存在明显不足。为此提出了一种通过明确引入周围词汇信息而改进NAT模型局部性能力的方法。具体而言,在编码器和解码器两个方向上引入了混合分组线性变换,以获得更具局部感知性的表示。通过在WMT14英德与WMT16英罗两个数据集上进行实验,结果表明该方法以微弱的速度代价分别提高了0.7与1.03个BLEU分数,这表明该研究方法在改善NAT模型的局部性特征提取方面具有显著的效果和潜力。