检索结果-内蒙古大学图书馆

Asymptotic Inference in the Random Coefficient Autoregressive Model with Time-functional Variance Noises

Acta Mathematicae Applicatae Sinica 2024年第2期40卷 320-346页

作者： En-wen ZHU Zi-wei DENG Han-jun ZHANG Jun CAO Xiao-hui LIU Department of Mathematics and Statistics Changsha University of Science and TechnologyChangsha 410114China School of Mathematics and Computational Science Xiangtan UniversityXiangtan 411105China School of Statistics and Data Science and Key Laboratory of Data Science in Finance and EconomicsJiangxi University of Finance and EconomicsNanchang 330013China

This paper considers the random coefficient autoregressive model with time-functional variance noises,hereafter the RCA-TFV *** first establish the consistency and asymptotic normality of the conditional least squares estimator for the constant *** semiparametric least squares estimator for the variance of the random coefficient and the nonparametric estimator for the variance function are constructed,and their asymptotic results are reported.A simulation study is presented along with an analysis of real data to assess the performance of our method in finite samples.

关键词： random coefficient autoregressive model time-functional variance conditional least squares semiparametric least squares

来源：评论

学校读者我要写书评

暂无评论

Error Analysis of Three-Layer Neural Network Trained With PGD for Deep Ritz Method

引用

IEEE Transactions on Information Theory 2025年第7期71卷 5512-5538页

作者： Jiao, Yuling Lai, Yanming Wang, Yang Wuhan University School of Artificial Intelligence National Center for Applied Mathematics in Hubei Hubei Key Laboratory of Computational Science School of Mathematics and Statistics Wuhan430072 China The Hong Kong University of Science and Technology Department of Mathematics Hong Kong

Machine learning is a rapidly advancing field with diverse applications across various domains. One prominent area of research is the utilization of deep learning techniques for solving partial differential equations (PDEs). In this work, we specifically focus on employing a three-layer tanh neural network within the framework of the deep Ritz method (DRM) to solve second-order elliptic equations with three different types of boundary conditions. We perform projected gradient descent (PDG) to train the three-layer network and we establish its global convergence. To the best of our knowledge, we are the first to provide a comprehensive error analysis of using overparameterized networks to solve PDE problems, as our analysis simultaneously includes estimates for approximation error, generalization error, and optimization error. We present error bound in terms of the sample size n and our work provides guidance on how to set the network depth, width, step size, and number of iterations for the projected gradient descent algorithm. Importantly, our assumptions in this work are classical and we do not require any additional assumptions on the solution of the equation. This ensures the broad applicability and generality of our results. © 1963-2012 IEEE.

关键词： Partial differential equations

来源：评论

学校读者我要写书评

暂无评论

The challenges and opportunities of women working in weaving cultural clothes at Bahir-Dar City, Bahirdar, Ethiopia

引用

Discover Global Society 2025年第1期3卷 1-9页

作者： Getachew, Tatek Alemu, Chekol Wudu, Habitamu Department of Gender and Development Studies Faculty of Social Science and Humanities Gambella University Gambella Ethiopia Department of Statistics College of Natural and Computational Sciences Gambella University Gambella Ethiopia

Background: Cultural weaving is a crucial component of the cotton industry, linking rural and urban households through traditional handcrafts and providing income for women, thereby enhancing family livelihoods. The demand for hand-woven garments is on the rise, although a study from 2003 to 2009 revealed a decrease in skill-based wage premiums and a slight wage penalty for women in the garment sector. Traditionally, men and women have collaborated in fabric production, with men handling weaving and women focusing on decoration. Ethiopia is highlighted as a prominent African country for its rich cultural clothing and diverse ethnic heritage. Method: The study employed a qualitative research method with a case study design. Participants were selected through purposive and availability sampling for semi-structured interviews and focus group discussions. After reaching saturation with fourteen weavers and key informants, data were analyzed using thematic analysis. Result: The study highlights that women weavers of cultural clothes face numerous challenges, including socio-cultural issues, psychological problems, and economic difficulties such as material shortages and outdated technology. Despite these obstacles, there are opportunities for improvement through institutional support, training programs, and social networking. Ultimately, these women benefit from income generation, work flexibility, skill development, and enhanced social satisfaction, positively impacting their lives and their families' livelihoods. Conclusion: The study suggests that the Women, Children, and Social Affairs Office of Keeble should systematically address the challenges faced by women weavers, particularly regarding access to essential services and materials. Additionally, it calls for a shift in community attitudes to recognize weaving as a valuable profession that can improve lives rather than being viewed negatively. © The Author(s) 2025.

关键词： Bahir-Dar Cities Clothes Cultural Weaving Women

来源：评论

学校读者我要写书评

暂无评论

Stability of Equilibria in a One Dimensional Model for Morpho–Poroelasticity for Soft Tissues

Stability of Equilibria in a One Dimensional Model for Mo...

引用

European Conference on Numerical Mathematics and Advanced Applications, ENUMATH 2023

作者： Asghar, Sabia Vermolen, Fred Computational Mathematics Group Department of Mathematics and Statistics University of Hasselt Hasselt Belgium Data Science Institute University of Hasselt Hasselt Belgium

ISBN: (纸本)9783031861680

We propose a novel one–dimensional model for morpho–poroelasticity. This model combines mechanical displacement with tissue growth or shrinkage. This tissue growth or shrinkage may be caused by biological processes such as secretion of collagen, cell proliferation or by micro-structural changes of the collagen phase. The central focus of our study revolves around a comprehensive linear stability analysis of the equilibrium state within the proposed model. This analytical approach allows us to assess the stability of the system under different perturbation conditions which is critical for predicting the behavior of the system over time and under various external influences. Additionally, numerical experiments are included to visually demonstrate the proposed concept. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Linear stability analysis

来源：评论

学校读者我要写书评

暂无评论

Data-Driven Learning of the Generalized Langevin Equation with State-Dependent Memory

引用

Physical Review Letters 2024年第7期133卷 077301-077301页

作者： Pei Ge Zhongqiang Zhang Huan Lei Department of Computational Mathematics Science and Engineering Department of Mathematical Sciences Department of Statistics and Probability

We present a data-driven method to learn stochastic reduced models of complex systems that retain a state-dependent memory beyond the standard generalized Langevin equation with a homogeneous kernel. The constructed model naturally encodes the heterogeneous energy dissipation by jointly learning a set of state features and the non-Markovian coupling among the features. Numerical results demonstrate the limitation of the standard generalized Langevin equation and the essential role of the broadly overlooked state-dependency nature in predicting molecule kinetics related to conformation relaxation and transition.

关键词： Coarse graining Machine learning Multiscale modeling

来源：评论

学校读者我要写书评

暂无评论

THE CONTAGION NUMBER: HOW FAST CAN A DISEASE SPREAD?

Decision Making: Applications in Management and Engineering

引用

Decision Making: Applications in Management and Engineering 2023年第1期6卷 219-239页

作者： Blessley, Misty Davila, Randy Hale, Trevor Pepper, Ryan Statistics Operations and Data Science Department Temple University United States Computational and Applied Mathematics Department Rice University United States Information and Operations Management Department Texas A&M University United States Mathematics and Statistics Department University of Houston - Downtown United States

The overall purpose of this paper is to define a new metric on the spreadability of a disease. Herein, we define a variant of the well-known graph-theoretic burning number (BN) metric that we coin the contagion number (CN). We aver that the CN is a better metric to model disease spread than the BN as the CN concentrates on first time infections. This is important because the Centers for Disease Control and Prevention report that COVID-19 reinfections are rare. This paper delineates a novel methodology to solve for the CN of any tree, in polynomial time, which addresses how fast a disease could spread (i.e., a worst-cast analysis). We then employ Monte Carlo simulation to determine the average contagion number (ACN) (i.e., a most-likely analysis) of how fast a disease would spread. The latter is analyzed on scale-free graphs, which are specifically designed to model human social networks (sociograms). We test our method on some randomly generated scale-free graphs and our findings indicate the CN to be a robust, tractable (the BN is NP-hard even for a tree), and effective disease spread metric for decision makers. The contributions herein advance disease spread understanding and reveal the importance of the underlying network structure. Understanding disease spreadability informs public policy and the associated managerial allocation decisions. © 2023 by the authors.

关键词： COVID-19

来源：评论

学校读者我要写书评

暂无评论

Adaptive Sparse Grid Discontinuous Galerkin Method:Review and Software Implementation

引用

Communications on Applied Mathematics and Computation 2024年第1期6卷 501-532页

作者： Juntao Huang Wei Guo Yingda Cheng Department of Mathematics and Statistics Texas Tech UniversityLubbockTX79409USA Department of Computational Mathematics Science and EngineeringMichigan State UniversityEast LansingMI48824USA Department of Mathematics Michigan State UniversityEast LansingMI48824USA

This paper reviews the adaptive sparse grid discontinuous Galerkin(aSG-DG)method for computing high dimensional partial differential equations(PDEs)and its software *** C++software package called AdaM-DG,implementing the aSG-DG method,is available on GitHub at https://***/JuntaoHuang/*** package is capable of treating a large class of high dimensional linear and nonlinear *** review the essential components of the algorithm and the functionality of the software,including the multiwavelets used,assembling of bilinear operators,fast matrix-vector product for data with hierarchical *** further demonstrate the performance of the package by reporting the numerical error and the CPU cost for several benchmark tests,including linear transport equations,wave equations,and Hamilton-Jacobi(HJ)equations.

关键词： Adaptive sparse grid Discontinuous Galerkin High dimensional partial differential equation Software development

来源：评论

学校读者我要写书评

暂无评论

Explainable Conformer Network for Detection of COVID-19 Pneumonia from Chest CT Scan: From Concepts toward Clinical Explainability

引用

Computers, Materials & Continua 2024年第1期78卷 1171-1187页

作者： Mohamed Abdel-Basset Hossam Hawash Mohamed Abouhawwash S.S.Askar Alshaimaa A.Tantawy Faculty of Computers and Informatics Zagazig UniversityZagazig44519Egypt Department of Computational Mathematics Scienceand Engineering(CMSE)Michigan State UniversityEast LansingMI48824USA Department of Mathematics Faculty of ScienceMansoura UniversityMansoura35516Egypt Department of Statistics and Operations Research College of ScienceKing Saud UniversityP.O.Box 2455Riyadh11451Saudi Arabia

The early implementation of treatment therapies necessitates the swift and precise identification of COVID-19 pneumonia by the analysis of chest CT *** study aims to investigate the indispensable need for precise and interpretable diagnostic tools for improving clinical decision-making for COVID-19 *** paper proposes a novel deep learning approach,called Conformer Network,for explainable discrimination of viral pneumonia depending on the lung Region of Infections(ROI)within a single modality radiographic CT ***,an efficient U-shaped transformer network is integrated for lung image ***,a robust transfer learning technique is introduced to design a robust feature extractor based on pre-trained lightweight Big Transfer(BiT-L)and finetuned on medical data to effectively learn the patterns of infection in the input ***,this work presents a visual explanation method to guarantee clinical explainability for decisions made by Conformer *** evaluation of real-world CT data demonstrated that the diagnostic accuracy of ourmodel outperforms cutting-edge studies with statistical *** Conformer Network achieves 97.40% of detection accuracy under cross-validation *** model not only achieves high sensitivity and specificity but also affords visualizations of salient features contributing to each classification decision,enhancing the overall transparency and trustworthiness of our *** findings provide obvious implications for the ability of our model to empower clinical staff by generating transparent intuitions about the features driving diagnostic decisions.

关键词： Deep learning COVID-19 multi-modal medical image fusion diagnostic image fusion

来源：评论

学校读者我要写书评

暂无评论

Securing unmanned aerial vehicle—heterogeneous networks using functional encryption scheme

引用

Multimedia Tools and Applications 2025年 1-19页

作者： Gupta, Sachin Kumar Gupta, Parul Singh, Pawan Department of Electronics and Communication Engineering Central University of Jammu UT of Jammu and Kashmir Jammu181143 India Computer Science of Engineering J.B. Institute of Technology Uttarakhand Dehradun248197 India Department of Computer Science School of Mathematics Statistics and Computational Sciences Central University of Rajasthan Ajmer- 305817 Rajasthan India

In today's scenario, as the internet expands at a faster pace, the number of data consumers also increases at an exponential rate. As the range and number of users increased, a change from traditional homogeneous networks to heterogeneous networks is in demand. However, heterogeneous networks' primary focus is to give a higher quality of service criteria to users. Furthermore, in a heterogeneous network enabled by unmanned aerial vehicles, a large number of users and devices are active. In such a diverse environment, intruder nodes may efficiently operate and transmit numerous harmful actions throughout the network. As a result, the network's entire communication is open to many types of security threats. Therefore, to secure the communication, we used the functional encryption scheme, which allows us to protect the data against intrusion attacks. The whole procedure of establishing a functional encryption scheme in unmanned aerial vehicles integrated heterogeneous network is proposed in this study in two phases: the first phase between user equipment and micro base station, and the second phase between micro base station and unmanned aerial vehicles. The proposed approach is validated using the simulation tool namely Automated Validation of Internet Security Protocols and Applications. The outcome of the security validation ensures that the proposed methodology provides the desired security and robustness to the network. © The Author(s), under exclusive licence to Springer science+Business Media, LLC, part of Springer Nature 2025.

关键词： Network intrusion

来源：评论

学校读者我要写书评

暂无评论

Numerical Solution of a One-Dimensional Nonlocal Helmholtz Equation by Perfectly Matched Layers

引用

Numerical Mathematics(Theory,Methods and Applications) 2022年第2期15卷 387-414页

作者： Yu Du Jiwei Zhang Department of Mathematics Xiangtan UniversityHunan 411105China School of Mathematics and Statistics Hubei Key Laboratory of Computational ScienceWuhan UniversityWuhan 430072China

We consider the computation of a nonlocal Helmholtz equation by using perfectly matched layer(PML).We first derive the nonlocal PML equation by extending PML modifications from the local operator to the nonlocal operator of integral *** that,we give stability estimates of some weighted-average values of the nonlocal Helmholtz solution and prove that(i)the weighted-average value of the nonlocal PML solution decays exponentially in PML layers in one case;(ii)in the other case,the weighted-average value of the nonlocal Helmholtz solution itself decays exponentially outside some *** for a typical kernel functionγ_(1)(s)=1/2 e^(−|s|),we obtain the Green’s function of the nonlocal Helmholtz equation,and use the Green’s function to further prove that(i)the nonlocal PML solution decays exponentially in PML layers in one case;(ii)in the other case,the nonlocal Helmholtz solution itself decays exponentially outside some *** on our theoretical analysis,the truncated nonlocal problems are discussed and an asymptotic compatibility scheme is also introduced to solve the resulting truncated ***,numerical examples are provided to verify the effectiveness and validation of our nonlocal PML strategy and theoretical findings.

关键词： Nonlocal wave propagation Helmholtz equation perfectly matched layer asymptotic compatibility scheme Green’s function

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：