检索结果-内蒙古大学图书馆

A high ORDER SCHEME FOR FRACTIONAL DIFFERENTIAL EQUATIONS WITH THE CAPUTO-HADAMARD DERIVATIVE

Journal of Computational Mathematics 2025年第3期43卷 615-640页

作者： Xingyang Ye Junying Cao Chuanju Xu School of Science Jimei UniversityXiamen 361021China School of Data Science and Information Engineering Guizhou Minzu UniversityGuiyang 550025China School of Mathematical Sciences and Fujian Provincial Key Laboratory of Mathematical Modeling and High Performance Scientific Computing Xiamen UniversityXiamen 361005China

In this paper,we consider numerical solutions of the fractional diffusion equation with theαorder time fractional derivative defined in the Caputo-Hadamard sense.A high order time-stepping scheme is constructed,analyzed,and numerically *** contribution of the paper is twofold:1)regularity of the solution to the underlying equation is investigated,2)a rigorous stability and convergence analysis for the proposed scheme is performed,which shows that the proposed scheme is 3+αorder *** numerical examples are provided to verify the theoretical statement.

关键词： Caputo-Hadamard derivative Fractional differential equations high order scheme Stability and convergence analysis

来源：评论

学校读者我要写书评

暂无评论

A Cross-domain Radar Emitter Recognition Method with Few-shot Learning 4

A Cross-domain Radar Emitter Recognition Method with Few-sho...

引用

4th International Symposium on Computer Engineering and Intelligent Communications, ISCEIC 2023

作者： Luo, Yixian Liu, Tianrui Li, Xueqiong Liu, Hengzhu Institute for Quantum Information State Key Laboratory of High Performance Computing National University of Defense Technology Changsha China College of Computer National University of Defense Technology Changsha China

ISBN: (纸本)9798350306323

In many realistic scenarios, it is necessary but challenging to acquire a large number of annotated radar emitter samples for training a recognition model. This study proposes a cross-domain radar emitter recognition method with few-shot learning, which introduces model-agnostic meta-learning (MAML) to recognize radar emitter and improves it to adapt to various types of radar emitter in different domains without spending a lot of time and data to retrain the model. This method can learn an ideal initialization parameter with a few source domain samples, and then initialize with this parameter on a completely different target domain. It can obtain good generalization effect by fine-tuning with fewer samples, so as to realize cross-domain recognition of radar emitter. Simulation results show that the accuracy of the proposed method can reach more than 90% in high-noise target domains with completely different data distribution from the source domain, which shows its superiority in recognition performance and sample size compared with other radar emitter recognition methods. © 2023 IEEE.

关键词： Learning systems

来源：评论

学校读者我要写书评

暂无评论

A Fixed-Point Fast Sweeping WENO Method with Inverse Lax-Wendroff Boundary Treatment for Steady State of Hyperbolic Conservation Laws

引用

Communications on Applied Mathematics and Computation 2023年第1期5卷 403-427页

作者： Liang Li Jun Zhu Chi-Wang Shu Yong-Tao Zhang Key Laboratory of Mathematical Modelling and High Performance Computing of Air Vehicles(NUAA) MIITNanjing University of Aeronautics and AstronauticsNanjing 210016JiangsuChina State Key Laboratory of Mechanics and Control of Mechanical Structures and Key Laboratory of Mathematical Modelling and High Performance Computing of Air Vehicles(NUAA) MIITNanjing University of Aeronautics and AstronauticsNanjing 210016JiangsuChina Division of Applied Mathematics Brown UniversityProvidenceRI 02912USA Department of Applied and Computational Mathematics and Statistics University of Notre DameNotre DameIN 46556USA

Fixed-point fast sweeping WENO methods are a class of efficient high-order numerical methods to solve steady-state solutions of hyperbolic partial differential equations(PDEs).The Gauss-Seidel iterations and alternating sweeping strategy are used to cover characteristics of hyperbolic PDEs in each sweeping order to achieve fast convergence rate to steady-state solutions.A nice property of fixed-point fast sweeping WENO methods which distinguishes them from other fast sweeping methods is that they are explicit and do not require inverse operation of nonlinear local ***,they are easy to be applied to a general hyperbolic *** deal with the difficulties associated with numerical boundary treatment when high-order finite difference methods on a Cartesian mesh are used to solve hyperbolic PDEs on complex domains,inverse Lax-Wendroff(ILW)procedures were developed as a very effective approach in the *** this paper,we combine a fifthorder fixed-point fast sweeping WENO method with an ILW procedure to solve steadystate solution of hyperbolic conservation laws on complex computing *** experiments are performed to test the method in solving various problems including the cases with the physical boundary not aligned with the *** results show highorder accuracy and good performance of the ***,the method is compared with the popular third-order total variation diminishing Runge-Kutta(TVD-RK3)time-marching method for steady-state *** examples show that for most of examples,the fixed-point fast sweeping method saves more than half CPU time costs than TVD-RK3 to converge to steady-state solutions.

关键词： Fixed-point fast sweeping methods Multi-resolution WENO schemes Steady state ILW procedure Convergence

来源：评论

学校读者我要写书评

暂无评论

Accelerating Blake3 in RISC-V 2

Accelerating Blake3 in RISC-V

引用

2nd International Conference on computing, Communication, Perception and Quantum technology, CCPQT 2023

作者： Zou, Xiaofeng Peng, Yuanxi Li, Tuo Kong, Lingjun Pang, Zhaochun Zhang, Lu National University of Defense Technology Institute for Quantum Information State Key Laboratory of High Performance Computing Changsha China Cloud Computing Equipment Innovation Center Second Research Institute Jinan China

ISBN: (纸本)9798350342697

This paper proposes a novel hardware design to accelerate the Blake3 hash algorithm, a cryptographic hash function, on RISC-V architecture, using both vector extension (V1.0) and a specially designed Blake3 instruction. The design leverages the parallelism and simplicity of BLAKE3 to achieve high throughput and low latency, implementing the core compression function using a custom instruction set architecture that supports vector operations and constant computing. The Blake3 compression function is speed up in architecture based on hardware/software co-design. The design achieves a speed-up of 10 times for the compression function compare with a single core of 2.7GHz Xeon 8280 and 10% faster than an AVX512 implementation. © 2023 IEEE.

关键词： Hash functions

来源：评论

学校读者我要写书评

暂无评论

Context-Driven Index Trimming: A Data Quality Perspective to Enhancing Precision of RALMs

Context-Driven Index Trimming: A Data Quality Perspective to...

引用

2024 Conference on Empirical Methods in Natural Language Processing, EMNLP 2024

作者： Ma, Kexin Jin, Ruochun Wang, Haotian Wang, Xi Chen, Huan Tang, Yuhua Wang, Qian Institute for Quantum Information State Key Laboratory of High Performance Computing China College of Computer Science and Technology National University of Defense Technology Changsha China Intelligent Game and Decision Lab Academy of Military Science Beijing China

ISBN: (纸本)9798891761681

Retrieval-Augmented Large Language Models (RALMs) have made significant strides in enhancing the accuracy of generated responses. However, existing research often overlooks the data quality issues within retrieval results, often caused by inaccurate existing vector-distance-based retrieval methods. We propose to boost the precision of RALMs' answers from a data quality perspective through the Context-Driven Index Trimming (CDIT) framework, where Context Matching Dependencies (CMDs) are employed as logical data quality rules to capture and regulate the consistency between retrieved contexts. Based on the semantic comprehension capabilities of Large Language Models (LLMs), CDIT can effectively identify and discard retrieval results that are inconsistent with the query context and further modify indexes in the database, thereby improving answer quality. Experiments demonstrate average improvement of 3.75% in accuracy on challenging question-answering tasks. Also, the flexibility of CDIT is verified through its compatibility with various language models and indexing methods, which offers a promising approach to bolster RALMs' data quality and retrieval precision jointly. © 2024 Association for Computational Linguistics.

关键词： Data accuracy

来源：评论

学校读者我要写书评

暂无评论

A Novel Spectral Method for the Subdiffusion Equation 13th

A Novel Spectral Method for the Subdiffusion Equation

引用

13th International Conference on Spectral and high Order Methods, ICOSAHOM 2021

作者： Xu, Chuanju Zeng, Wei School of Mathematical Sciences and Fujian Provincial Key Laboratory of Mathematical Modeling and High Performance Scientific Computing Xiamen University Xiamen China

ISBN: (纸本)9783031204319

In this paper, we design and analyze a novel spectral method for the subdiffusion equation. As it has been known, the solutions of this equation are usually singular near the initial time. Consequently, direct application of the traditional high-order numerical methods is inefficient. We try to overcome this difficulty in a novel approach by combining variable transformation techniques with spectral methods. The idea is to first use suitable variable transformation to re-scale the underlying equation, then construct spectral methods for the re-scaled equation. We establish a new variational framework based on the ψ-fractional Sobolev spaces. This allows us to prove the well-posedness of the associated variational problem. The proposed spectral method is based on the variational problem and generalized Jacobi polynomials to approximate the re-scaled fractional differential equation. Our theoretical and numerical investigation show that the proposed method is exponentially convergent for general right hand side functions, even though the exact solution has very limited regularity. Implementation details are also provided, along with a series of numerical examples to show the efficiency of the proposed method. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Sobolev spaces

来源：评论

学校读者我要写书评

暂无评论

Design and Implementation of a Compiler Supporting RISC-V Custom Cryptographic and Vector Instructions 23

Design and Implementation of a Compiler Supporting RISC-V Cu...

引用

7th International Conference on Computer Science and Application Engineering, CSAE 2023

作者： Zou, Xiaofeng Peng, Yuanxi Zhang, Qing Institute for Quantum Information State Key Laboratory of High Performance Computing National University of Defense Technology Changsha China Second Research Department Cloud Computing Equipment Industry Innovation Center Jinan China

ISBN: (纸本)9798400700590

Post-quantum cryptographic algorithms capable of resisting quantum computing attacks have received increasing attention in recent years, especially lattice-based cryptographic algorithms have become mainstream. Since their specialization and complex computation, the cryptographic computation is inefficient on general-purpose processors. In order to improve the performance of the processor in post-quantum cryptography computing, we have extended a set of cryptographic and vector instruction sets for the CRYSTALS-Kyber algorithm, and implemented support for custom cryptographic and vector instructions based on the open-source toolchain. These efforts can realize the compilation and disassembly of the CRYSTALS-Kyber encryption/decryption algorithm programs, and optimized the performance of the compilation. This paper mainly introduces how to design an extended instruction set based on the target algorithm and enable the compiler to support these instructions. Compared to the situation before extending custom instructions, the total number of instructions for key generation, encryption, and decryption assembly programs has decreased by 3651 times, and the total number of execution cycles has decreased by 2195 times. © 2023 ACM.

关键词： Program compilers

来源：评论

学校读者我要写书评

暂无评论

Experimental review on Majorana zero-modes in hybrid nanowires

引用

Science China(Physics,Mechanics & Astronomy) 2021年第10期64卷 38-53页

作者： Ji-Bang Fu Bin Li Xin-Fang Zhang Guang-Zheng Yu Guang-Yao Huang Ming-Tang Deng Institute for Quantum Information&State Key Laboratory of High Performance Computing College of Computer Science and TechnologyNational University of Defense TechnologyChangsha 410073China

As the condensed matter analog of Majorana fermion, the Majorana zero-mode is well known as a building block of fault-tolerant topological quantum computing. This review focuses on the recent progress of Majorana experiments, especially experiments about semiconductor-superconductor hybrid devices. We first sketch Majorana zero-mode formation from a bottom-up view,which is more suitable for beginners and experimentalists. Then, we survey the status of zero-energy state signatures reported recently, from zero-energy conductance peaks, the oscillations, the quantization, and the interactions with extra degrees of freedom. We also give prospects of future experiments for advancing one-dimensional semiconductor nanowire-superconductor hybrid materials and devices.

关键词： electronic transport in nanoscale materials and structures quantum wires proximity efect superconducting low-dimensional structures

来源：评论

学校读者我要写书评

暂无评论

An Unsupervised Concrete Crack Detection Method Based on nnU-Net

An Unsupervised Concrete Crack Detection Method Based on nnU...

引用

International Conference on Image, Vision and Intelligent Systems, ICIVIS 2021

作者： Li, Xinyang Yang, Shaowu Liu, Hengzhu State Key Laboratory of High Performance Computing College of Computer National University of Defense Technology Changsha410073 China

ISBN: (纸本)9789811669620

Concrete crack detection is critical to the maintenance of infrastructure. Neural network-based vision methods are widely used to address this challenging task. Current supervised learning methods rely heavily on a large amount of labeled data. To tackle this problem, we proposed an unsupervised concrete crack detection method based on nnU-Net, in which a new reconstruction strategy is applied. Specifically, the input image is first passed to the trained model, and the output image is used as the input image of the final model to reconstruct the original image. We introduced the weighted sum of L2 and SSIM as the loss function of the network to improve the reconstruction ability of the model. We analyzed the proposed method and compared it with the baseline method, which shows obvious improvement. The method has an AP of 0.84 and AUROC of 0.85 on the test set and can give rough estimate of concrete crack location. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Crack detection

来源：评论

学校读者我要写书评

暂无评论

A Physics-Informed Structure-Preserving Numerical Scheme for the Phase-Field Hydrodynamic Model of Ternary Fluid Flows

引用

Numerical Mathematics(Theory,Methods and Applications) 2023年第3期16卷 565-596页

作者： Qi Hong Yuezheng Gong Jia Zhao School of Mathematics Nanjing University of Aeronautics and Astronautics/Key Laboratory of Mathematical Modelling and High Performance Computing of Air Vehicles(NUAA)MIITNanjing 211106China Department of Mathematics and Statistics Utah State UniversityLoganUT84322USA

Phase-field models are widely used in studying multiphase flow *** the complexity and strong nonlinearity,designing accurate,efficient,and stable numerical algorithms to solve these models has been an active research field for *** paper proposes a novel numerical scheme to solve a highly cited and used phase field hydrodynamic model for simulating ternary phase fluid *** main novelty is the introduction of a supplementary variable to reformulate the original problem into a constrained optimization *** reformulation leads to several advantages for our proposed numerical algorithms compared with many existing numerical techniques for solving this ***,the developed schemes allow more straightforward calculations for the hydrodynamic phase-field models by solving a few decoupled Helmholtz or Poisson-type systems with a constant precomputable coefficient matrix,remarkably reducing the computational ***,the numerical schemes can maintain mass conservation and energy dissipation at the discrete ***,the developed scheme based on the secondorder backward difference formula respects the original energy dissipation law that differs from many existing schemes,such as the IEQ,SAV,and Lagrange multiplier approaches for which a modified energy dissipation law is ***,rigorous proof of energy stability and practical implementation strategies are *** conduct adequate 2D and 3D numerical tests to demonstrate the proposed schemes’accuracy and effectiveness.

关键词： Energy stable phase field Cahn-Hilliard-Navier-Stokes supplementary variable method

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：