检索结果-内蒙古大学图书馆

Phase-coherence dynamics of frequency-comb emission via high-order harmonic generation in few-cycle pulse trains

Chinese physics B 2023年第3期32卷 205-211页

作者：梁畅通张晶晶李鹏程 Research Center for Advanced Optics and Photoelectronics Department of PhysicsCollege of ScienceShantou UniversityShantou 515063China Key Laboratory of Intelligent Manufacturing Technology of the Ministry of Education Shantou UniversityShantou 515063China Institute of Applied Physics and Computational Mathematics Beijing 100088China

Frequency-comb emission via high-order harmonic generation(HHG)provides an alternative method for the coherent vacuum ultraviolet(VUV)and extreme ultraviolet(XUV)radiation at ultrahigh repetition *** particular,the temporal and spectral features of the HHG were shown to carry profound insight into frequency-comb emission *** we present an ab initio investigation of the temporal and spectral coherence of the frequency comb emitted in HHG of He atom driven by few-cycle pulse *** find that the emission of frequency combs features a destructive and constructive coherences caused by the phase interference of HHG,leading to suppression and enhancement of frequency-comb *** results reveal intriguing and substantially different nonlinear optical response behaviors for frequency-comb emission via *** dynamical origin of frequency-comb emission is clarified by analyzing the phase coherence in HHG processes in *** results provide fresh insight into the experimental realization of selective enhancement of frequency comb in the VUV–XUV regimes.

关键词： high-order harmonic generation frequency comb time-dependent Schro¨dinger equation intense laser field systems

来源：评论

学校读者我要写书评

暂无评论

Molecule opacity study on low-lying states of CS

引用

Chinese physics B 2022年第10期31卷 362-370页

作者： Rui Li Jiqun Sang Xiaohe Lin Jianjun Li Guiying Liang Yong Wu Department of Physics College of ScienceQiqihar UniversityQiqihar 161006China National Key Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Faculty of Foundation Space Engineering UniversityBeijing 101416China School of Data Science and Artificial Intelligence Jilin Engineering Normal UniversityChangchun 130052China HEDPS Center for Applied Physics and TechnologyPeking UniversityBeijing 100084China

CS molecule, which plays a key role in atmospheric and astrophysical circumstances, has drawn great attention for long time. Owing to its large state density, the detailed information of the electronic structure of CS is still lacking. In this work, the high-level MRCI+Q method is used to compute the potential energy curves, dipole moments and transition dipole moments of singlet and triplet states correlated with the lowest dissociation limit of CS, based on which high accurate vibration-rotation levels and spectroscopic constants of bound states are evaluated. The opacity of CS relevant to atmospheric circumstance is computed at a pressure of 100 atms for different temperatures. With the increase of temperature,band systems from different transitions mingle with each other, and band boundaries become blurred, which are originated from the increased population on vibrational excited states and electronic excited states at high temperature.

关键词： CS transition dipole moment opacity excited state

来源：评论

学校读者我要写书评

暂无评论

Numerical solution hybridized by machine- leaning-based algorithm to provide an efficient method for analyzing thermomechanical shock behavior of the circumferentially-graded graphene-plates reinforced composite sandwich panel (sept, 10.1080/15376494.2023.2195417, 2023)

引用

MECHANICS OF ADVANCED MATERIALS AND STRUCTURES 2024年第29期31卷 12345-12348页

作者： Han, Shaoyong Ye, Qianqian Hakamy, A. Abd-Elnaiem, Alaa M. Changzhou Vocational Institute of Industry Technology Changzhou Jiangsu China Postdoctoral Scientific Research Workstation Bank of Zhengzhou Zhengzhou Henan China School of Data Science and Artificial Intelligence Wenzhou University of Technology Wenzhou Zhejiang China Department of Physics Faculty of Applied Science Umm Al-Qura University Makkah Saudi Arabia Physics Department Faculty of Science Assiut University Assiut Egypt

The present research bridges the gap between a numerical solution with efficient machine-learning-based algorithms to provide a strong platform for predicting thermomechanical shock behavior of the sandwich cylindrical panels with polymer-made core and circumferentially-graded graphene-plates reinforced (CG-GPLR) nanocomposite face-sheets. The comprehensive declaration of the elasticity theory is considered to establish the governing equations of the system in three orthogonal directions. The well-known Lord-Shulman heat transfer theorem is implemented to present the time-variant nature of the system’s heat. The differential quadrature method (DQM) is used as a numerical approach to solve the spatial dependency of the governing differential equations. While the Laplace transform solves the time dependency of the governing differential equations. In order to decline the computational cost of predicting the time-variant analysis of the thermomechanical shock response of the system, an efficient machine-learning-based algorithm is employed in a way that it only requires the thermomechanical shock information of the selective set of points known as the training set. After completion of the training procedure, this machine-learning predictor can easily predict the thermoelastic response of all points included either as the train set or a new point. Validation of the applied solution is performed through a comparative process between the present results with those determined in the published literature. The results of this study are in excellent compatibility with those obtained in a solo numerical solution.

关键词： Coupled thermoelasticity analysis sandwich cylindrical shell optimized machine-learning regressor spatial and temporal stress distribution thermomechanical shock response

来源：评论

学校读者我要写书评

暂无评论

Multi-armed bandits for resource efficient, online optimization of language model pre-training: the use case of dynamic masking 61

Multi-armed bandits for resource efficient, online optimizat...

引用

Findings of the Association for Computational Linguistics, ACL 2023

作者： Urteaga, Iñigo Lancewicki, Tomer Draïdia, Moulay-Zaïdane Khadivi, Shahram Applied Physics and Applied Mathematics Data Science Institute Columbia University New YorkNY United States Walmart Global Tech United States Data Science Institute Columbia University New YorkNY United States eBay Inc. Aachen Germany

ISBN: (纸本)9781959429623

We design and evaluate a Bayesian optimization framework for resource efficient pretraining of Transformer-based language models (TLMs). TLM pre-training requires high computational resources and introduces many unresolved design choices, such as selecting its pre-training hyperparameters. We propose a multi-armed bandit framework for the sequential selection of pre-training hyperparameters, aimed at optimizing language model performance, in a resource efficient manner. We design a Thompson sampling algorithm, with a surrogate Gaussian process reward model of the Masked Language Model (MLM) pretraining objective, for its sequential minimization. Instead of MLM pre-training with fixed masking probabilities, the proposed Gaussian process-based Thompson sampling (GP-TS) accelerates pre-training by sequentially selecting masking hyperparameters that improve performance. We empirically demonstrate how GP-TS pre-trains language models efficiently, i.e., it achieves lower MLM loss in fewer epochs, across a variety of settings. In addition, GP-TS pre-trained TLMs attain competitive downstream performance, while avoiding expensive hyperparameter grid search. GP-TS provides an interactive framework for efficient and optimized TLM pre-training that, by circumventing costly hyperparameter selection, enables substantial computational savings. © 2023 Association for Computational Linguistics.

关键词： Gaussian distribution

来源：评论

学校读者我要写书评

暂无评论

An Iterative Thresholding Method for the Minimum Compliance Problem

引用

Communications in Computational physics 2023年第4期33卷 1189-1216页

作者： Luyu Cen Wei Hu Dong Wang Xiaoping Wang Department of Mathematics Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina The Program in Applied and Computational Mathematics Princeton UniversityPrincetonNew JerseyUSA School of Science and Engineering The Chinese University of Hong KongShenzhenGuangdong 518172China Shenzhen International Center for Industrial and Applied Mathematics Shenzhen Research Institute of Big DataGuangdong 518172China

In this paper,we propose a simple energy decaying iterative thresholding algorithm to solve the two-phase minimum compliance *** material domain is implicitly represented by its characteristic function,and the problem is formulated into a minimization problem by the principle of minimum complementary *** prove that the energy is decreasing in each *** effective continuation schemes are proposed to avoid trapping into the local *** results on 2D isotropic linear material demonstrate the effectiveness of the proposed methods.

关键词： Minimum compliance convolution thresholding linear elasticity

来源：评论

学校读者我要写书评

暂无评论

A continuous symmetry breaking measure for finite clusters using Jensen-Shannon divergence

arXiv

引用

arXiv 2024年

作者： Lan, Ling Du, Qiang Billinge, Simon J.L. Department of Applied Physics and Applied Mathematics Columbia University New YorkNY10027 United States Department of Applied Physics and Applied Mathematics Data Science Institute Columbia University NY10027 United States

A quantitative measure of symmetry breaking is introduced that allows the quantification of which symmetries are most strongly broken due to the introduction of some kind of defect in a perfect structure. The method uses a statistical approach based on the Jensen-Shannon divergence. The measure is calculated by comparing the transformed atomic density function with its original. Software code is presented that carries the calculations out numerically using Monte Carlo methods. The behavior of this symmetry breaking measure is tested for various cases including finite size crystallites (where the surfaces break the crystallographic symmetry), atomic displacements from high symmetry positions, and collective motions of atoms due to rotations of rigid octahedra. The approach provides a powerful tool for assessing local symmetry breaking and offers new insights that can help researchers understand how different structural distortions affect different symmetry operations. © 2024, CC BY.

关键词： Atoms

来源：评论

学校读者我要写书评

暂无评论

Monitoring photochemical pollutants based on symbolic interval-valued data analysis

引用

Advances in data Analysis and Classification 2023年第4期17卷 897-926页

作者： Lin, Liang-Ching Guo, Meihui Lee, Sangyeol Department of Statistics and Institute of Data Science National Cheng Kung University Tainan Taiwan Department of Applied Mathematics National Sun Yat-sen University Kaohsiung Taiwan Department of Statistics Seoul National University Seoul08826 Korea Republic of

This study considers monitoring photochemical pollutants for anomaly detection based on symbolic interval-valued data analysis. For this task, we construct control charts based on the principal component scores of symbolic interval-valued data. Herein, the symbolic interval-valued data are assumed to follow a normal distribution, and an approximate expectation formula of order statistics from the normal distribution is used in the univariate case to estimate the mean and variance via the method of moments. In addition, we consider the bivariate case wherein we use the maximum likelihood estimator calculated from the likelihood function derived under a bivariate copula. We also establish the procedures for the statistical control chart based on the univariate and bivariate interval-valued variables, and the procedures are potentially extendable to higher dimensional cases. Monte Carlo simulations and real data analysis using photochemical pollutants confirm the validity of the proposed method. The results particularly show the superiority over the conventional method that uses the averages to identify the date on which the abnormal maximum occurred. © 2022, Springer-Verlag GmbH Germany, part of Springer Nature.

关键词： Control charts

来源：评论

学校读者我要写书评

暂无评论

Thermal optimization of MHD nanofluid over a wedge by using response surface methodology:Sensitivity analysis

引用

Propulsion and Power Research 2023年第4期12卷 556-567页

作者： Ahmed Zeeshan Dilawar Hussain Zaheer Asghar Muhammad Mubashir Bhatti Faisal Z.Duraihem Department of Mathematics&Statistics FBASInternational Islamic UniversityIslamabadH-10Islamabad 44000Pakistan Department of Mathematics Faculty of Natural and Health SciencesUniversity of BaltistanSkardu 16100Pakistan Centre for Mathematical Sciences Pakistan Institute of Engineering and Applied SciencesNiloreIslamabad 45650Pakistan Department of Physics and Applied Mathematics Pakistan Institute of Engineering and Applied SciencesNiloreIslamabad 45650Pakistan Department of Mathematics and System Sciences Shandong University of Science and TechnologyShandongChina Department of Mathematics College of ScienceKing Saud UniversityP.O.Box 2455Riyadh 11451Saudi Arabia

It is well documented that heat transfer is enhanced with addition of nanosized particles in ***,in a mechanical system there are variety of factors influences the heat *** factors are significant while others are *** this paper,authors will discuss sensitivity of different input parameters such as Le,Nt and Nb on output responses𝑁Nu_(x)and Sh_(x).To achieve this goal,the problem is modeled using basic conservation *** formulated model is a set of PDEs,which are converted to set of non-linear ODEs by using similarity *** these ODEs are solved numerically by using MATLAB built in package bvp4c and compared the numerical results with existing work and found good *** analysis is performed by employing RSM to determine the relationship between the input parameters such that 0.1≤Le≤1,0.1≤Nt≤1 and 0.1≤Nb≤1 and the output responses(Nu_(x)and Sh_(x)).ANOVA tables are generated by using *** using the ANOVA tables the correlations between input parameters and output response are *** check the validity of correlated equations,the residuals are plotted graphically and show best correlations between input parameters and output *** high values of R^(2)=98.65 and AdjR^(2)=97.43 for Nu_(x)and R^(2)=97.83 and AdjR^(2)=95.88 for Sh_(x)demonstrates the high validity of ANOVA results to perform sensitivity ***,we have conducted a sensitivity analysis of the responses and came to the important results that Nt and Nb is most sensitive to Nusselt number and Sherwood number respectively.

关键词： Sensitivity analysis Nusselt number Sherwood number Response surface methodology(RSM) Analysis of variance(ANOVA) Nano fluid

来源：评论

学校读者我要写书评

暂无评论

Neutrosophic Mean Estimators Using Extreme Indeterminate Observations in Sample Surveys

引用

Neutrosophic Sets and Systems 2025年 80卷 86-117页

作者： Yadav, Vinay Kumar Majhi, Deepak Alkhathami, Alia A. Prasad, Shakti Department of Data Sciences and Analytics School of Social Sciences M S Ramaiah University of Applied Sciences Bengaluru560054 India PG Department of Mathematics Veer Kunwar Singh University Bihar Ara802301 India Department of Basic Science College of Science and Theoretical Studies Saudi Electronic University Riyadh11673 Saudi Arabia Department of Mathematics National Institute of Technology Jamshedpur Jharkhand Jamshedpur831014 India

In classical statistics, research typically relies on precise data to estimate the population mean, especially when auxiliary information is available. However, in the presence of outliers, conventional statistical approaches that depend on accurate data and auxiliary information encounter challenges. The primary objective is to attain the most accurate population mean estimates while minimizing the mean square error. Neutrosophic statistics, a more attractive framework than classical statistics, deals with data characterized by imprecision and uncertainty. In this current article, we adapt Särndal’s strategy and introduce neutrosophic mean estimators, applying them to meteorological data, specifically stratified dew point data. In these proposed estimators, the incorporation of auxiliary information and the application of robust techniques address issues that arise due to outliers and imprecise observations. These factors can otherwise undermine the effectiveness of neutrosophic estimation methods. The article also suggests combining auxiliary information with extremely indeterminate neutrosophic observations, utilizing robust regression methods (Huber-M, Hampel-M, and Tukey-M), as well as the quantile regression technique. These approaches enhance the neutrosophic mean estimation process. The outcomes, which include the utilization of dew point data, showcase the superior performance of the proposed estimators compared to adapted estimators in a neutrosophic context. Ultimately, this study provides valuable insights by taking an initial step in defining and utilizing the concept of neutrosophic indeterminate extreme observations. © 2025, University of New Mexico. All rights reserved.

关键词： Mean square error

来源：评论

学校读者我要写书评

暂无评论

Optimal testing using combined test statistics across independent studies 37

Optimal testing using combined test statistics across indepe...

引用

37th Conference on Neural Information Processing Systems, NeurIPS 2023

作者： Vuursteen, Lasse van der Vaart, Aad Szabó, Botond van Zanten, Harry Delft Institute of Applied Mathematics Delft University of Technology Netherlands Department of Decision Sciences Institute for Data Science and Analytics Bocconi University Italy Mathematics Department Vrije Universiteit Amsterdam Netherlands

ISBN: (纸本)9781713899921

Combining test statistics from independent trials or experiments is a popular method of meta-analysis. However, there is very limited theoretical understanding of the power of the combined test, especially in high-dimensional models considering composite hypotheses tests. We derive a mathematical framework to study standard meta-analysis testing approaches in the context of the many normal means model, which serves as the platform to investigate more complex models. We introduce a natural and mild restriction on the meta-level combination functions of the local trials. This allows us to mathematically quantify the cost of compressing m trials into real-valued test statistics and combining these. We then derive minimax lower and matching upper bounds for the separation rates of standard combination methods for e.g. p-values and e-values, quantifying the loss relative to using the full, pooled data. We observe an elbow effect, revealing that in certain cases combining the locally optimal tests in each trial results in a sub-optimal meta-analysis method and develop approaches to achieve the global optima. We also explore the possible gains of allowing limited coordination between the trial designs. Our results connect meta-analysis with bandwidth constraint distributed inference and build on recent information theoretic developments in the latter field. © 2023 Neural information processing systems foundation. All rights reserved.

关键词： Statistics

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：