检索结果-内蒙古大学图书馆

A General Simplification and acceleration method for Distribution System Optimization Problems

PROTECTION AND CONTROL OF MODERN POWER SYSTEMS 2025年第1期10卷 148-167页

作者： Xiao, Jun Zhou, Yupeng She, Buxin Bao, Zhenyu Tianjin Univ Key Lab Minist Educ Smart Power Grids Tianjin 300072 Peoples R China Univ Tennessee Dept Elect Engn & Comp Sci Knoxville TN 37996 USA State Grid Zhejiang Elect Power Co Ltd Ningbo Power Supply Co Ningbo 315000 Peoples R China

Solving optimization problems plays a vital role in ensuring the secure and economic operation of distribution systems. To enhance computational efficiency, this paper proposes a general simplification and acceleration method for distribution system optimization problems. Firstly, the capacity boundary and voltage boundary model of distribution systems are established. The relative position between the two boundaries reflects the strength of capacity and voltage constraints, leading to the definition of two critical feeder lengths (CFLs) to quantify these strengths. Secondly, simplification criteria and an acceleration method are proposed. Given a distribution system, if the distance from the end load/DG node to the slack bus is less than the corresponding CFL, we can conclude that the capacity constraints are stricter than the voltage constraints. Then, the distribution system can be simplified by adopting DC power flow model or disregarding the voltage constraints. After that, the reference value tables of CFL are presented. Finally, the effectiveness of the proposed method is verified by exemplifying the method in network reconfiguration and reactive power optimization problems. By implementing the proposed acceleration method, a significant reduction in computation time is achieved while ensuring accuracy. This method applies to most urban distribution systems in optimization problems involving power flow equations or voltage constraints.

关键词： Economics Reactive power Computational modeling Optimization models Voltage Relaxation methods Protection Optimization Load flow Load modeling Distribution system optimization problem power flow equation security region simplification criteria acceleration method network reconfiguration reactive power optimization

来源：评论

学校读者我要写书评

暂无评论

Fast symplectic integrator for Nesterov-type acceleration method

引用

JAPAN JOURNAL OF INDUSTRIAL AND APPLIED MATHEMATICS 2025年第1期42卷 331-372页

作者： Goto, Shin-itiro Hino, Hideitsu Chubu Univ Ctr Math Sci & Artificial Intelligence 1200 Matsumoto cho Kasugai Aichi 4878501 Japan Inst Stat Math Dept Adv Data Sci Tachikawa Tokyo 1908562 Japan RIKEN AIP Tokyo 1030027 Japan

In this paper, explicit stable integrators based on symplectic and contact geometries are proposed for a family of non-autonomous ordinarily differential equations (ODEs) found in improving convergence rate of Nesterov's accelerated gradient method. Symplectic geometry is known to be suitable for describing Hamiltonian mechanics, and contact geometry is known as an odd-dimensional counterpart of symplectic geometry. Moreover, a procedure, called symplectization, is a known way to construct a symplectic manifold from a contact manifold, yielding autonomous Hamiltonian systems from contact ones. It is found in this paper that a previously investigated non-autonomous ODEs can be written as a contact Hamiltonian system family. Then, by developing and applying a symplectization of non-autonomous contact Hamiltonian vector fields expressing the non-autonomous ODEs, novel symplectic integrators are derived. Because the proposed symplectic integrators preserve hidden symplectic and contact structures in the ODEs, they are expected to be more stable than the Runge-Kutta method. Numerical experiments demonstrate that, as expected, the second-order symplectic integrator is stable and high convergence rates are achieved.

关键词： Convex optimization acceleration method Symplectic integrator Contact geometry Hamiltonian system

来源：评论

学校读者我要写书评

暂无评论

A dynamic-mode-decomposition-based acceleration method for unsteady adjoint equations at low Reynolds numbers

引用

Theoretical & Applied Mechanics Letters 2023年第5期13卷 353-356页

作者： Wengang Chen Jiaqing Kou Wenkai Yang Changzhou Institute of Technology Changzhou 213032China Institute of Aerodynamics RWTH Aachen UniversityWüllnerstraße 5a52062 AachenGermany

The computational cost of unsteady adjoint equations remains high in adjoint-based unsteady aerodynamic *** this letter,the solution of unsteady adjoint equations is accelerated by dynamic mode decomposi-tion(DMD).The pseudo-time marching of every real-time step is approximated as an infinite-dimensional linear dynamical ***,DMD is utilized to analyze the adjoint vectors sampled from these pseudo-time ***-order zero frequency mode is selected to accelerate the pseudo-time marching of unsteady adjoint equations in every real-time *** flow past a stationary circular cylinder and an unsteady aerodynamic shape optimization example,the efficiency of solving unsteady adjoint equations is significantly ***-sults show that one hundred adjoint vectors contains enough information about the pseudo-time dynamics,and the adjoint dominant mode can be precisely predicted only by five snapshots produced from the adjoint vectors,which indicates DMD analysis for pseudo-time marching of unsteady adjoint equations is efficient.

关键词： acceleration method Unsteady adjoint Dynamic mode decomposition Optimization efficiency

来源：评论

学校读者我要写书评

暂无评论

acceleration method FOR EVOLUTIONARY OPTIMIZATION OF VARIABLE CYCLE ENGINE

ACCELERATION METHOD FOR EVOLUTIONARY OPTIMIZATION OF VARIABL...

引用

ASME Turbomachinery Technical Conference and Exposition (Turbo Expo)

作者： Hao, Wang Zhou, Li Zhang, Xiaobo Wang, Zhanxue Northwestern Polytech Univ Sch Power & Energy Shaanxi Key Lab Internal Aerodynam Aeroengine Xian 710072 Peoples R China

ISBN: (纸本)9780791884058

Variable cycle engine (VCE) is considered as one of the best options for advanced military or commercial supersonic propulsion system. Variable geometries enable the engine to adjust performance over the entire the flight envelope but add complexity to the engine. Evolutionary algorithms (EAs) have been widely used in the design of VCE. The initial guesses of the engine model are generally set using design point information during evolutionary optimization. However, the design point information is not suitable for all situations. Without suitable initial guesses, the Newton-Raphson solver will not be able to reach the solution quickly, or even get a convergent solution. In this paper, a new method is proposed to obtain suitable initial guesses of VCE model during evolutionary optimization. Differential evolution (DE) algorithm is used to verify our method through a series of optimization cases of a double bypass VCE. The result indicates that the method can significantly reduce the VCE model call number during evolutionary optimization, which means a dramatic reduction in terms of evolution time. And the robustness of the optimization is not affected by the method. The method can also be used in the evolutionary optimization of other engines.

关键词： variable cycle engine evolutionary algorithm differential evolution algorithm evolutionary optimization initial guesses acceleration method

来源：评论

学校读者我要写书评

暂无评论

Cordic-based Softmax acceleration method of Convolution Neural Network on FPGA

Cordic-based Softmax Acceleration Method of Convolution Neur...

引用

IEEE International Conference on Artificial Intelligence and Information Systems (ICAIIS)

作者： Cao, Yongxiang Xiao, Wan'ang Jia, Jingdun Wu, Dehua Zhou, Weixin China Agr Univ Minist Agr & Rural Affairs Key Lab Agr Informatizat & Standardizat Coll Informat & Elect Engn Beijing Peoples R China Univ Chinese Acad Sci Ctr Mat Sci & Optoelect Engn Inst Semicond Chinese Acad Sci Beijing Peoples R China

ISBN: (纸本)9781728165905

With the vigorous development of computing power, Convolutional Neural Network (CNN) is developing rapidly, and new CNN structures with more layers and better performance continue to appear. Field Programmable Gate Array(FPGA) has gradually become the best choice for people to deploy and accelerate CNNs as a current research hotspot. This paper has studied the hardware acceleration method of FPGA to implement and simulate the Softmax layer of Alexnet on Vivado 2018.1. Combined with the features of FPGA, the Cordic algorithm is used to implement basic operations such as division and exponential functions, instead of consuming floating-point arithmetic resources. The paper proposes a method to shrink the convergence domain and analyzes the errors generated by the different digits of data after quantization and fixed-point inputs. The relative error of the Softmax layer exponential function is controlled below 0.0146% by reducing the bit width which satisfied the design requirements and saved resources. This method can complete the calculation and classification of the Softmax layer in 66.5 cycles without processing the layer data at fixed points, which greatly improves the calculation speed of the Softmax layer.

关键词： FPGA Cordic Softmax acceleration method

来源：评论

学校读者我要写书评

暂无评论

An acceleration method for Similar Time-Series Finding 1

引用

5th International Conference on Internet of Vehicles (IOV)

作者： Yuan, Yuan Sun, Qibo Zhou, Ao Gao, Siyi Wang, Shangguang Beijing Univ Posts & Telecommun State Key Lab Networking & Switching Technol Beijing Peoples R China

ISBN: (数字)9783030050818

ISBN: (纸本)9783030050818

Finding a time series subsequence that is similar to a specific time series is an important problem in trajectory data of vehicles analysis. The problem is made significantly harder for the massive and high-dimensional features of time series. The existing methods for finding the similar subsequences in time series have high time complexity and poor applicability to similar sub-sequence finding of different lengths. In this paper, we propose an acceleration method for similar time-series finding to address this issue. Firstly, our method defines and extracts the feature of the query sequence. Then, we use the feature as the key to search sequence with the same feature to form a candidate set. After that, in each sequence in candidate set, we filter the important points and add it into feature points list to hold the shape characteristics of original sequence better. Finally, Dynamic time warping (DTW) is used to find the similar time-series. Experiment results illustrate that the proposed method can improve the search efficiency and accuracy.

关键词： Time series Similarity searching Dimensions reduction acceleration method

来源：评论

学校读者我要写书评

暂无评论

acceleration method COMBINING BROADCAST AND INCREMENTAL DISTRIBUTED OPTIMIZATION ALGORITHMS

引用

SIAM JOURNAL ON OPTIMIZATION 2014年第4期24卷 1840-1863页

作者： Iiduka, Hideaki Hishinuma, Kazuhiro Meiji Univ Dept Comp Sci Tama Ku Kawasaki Kanagawa 2148571 Japan

This paper considers a networked system consisting of an operator, which manages the system, and a finite number of subnetworks with all users, and studies the problem of minimizing the sum of the operator's and all users' objective functions over the intersection of the operator's and all users' constraint sets. When users in each subnetwork can communicate with each other, they can implement an incremental subgradient method that uses the transmitted information from their neighbor users. Since the operator can communicate with users in the subnetworks, it can implement a broadcast distributed algorithm that uses all available information in the subnetworks. We present an iterative method combining broadcast and incremental distributed optimization algorithms. Our method has faster convergence and a wider range of application compared with conventional distributed algorithms. We also prove that under certain assumptions our method converges to the solution to the problem in the sense of the strong topology of a Hilbert space. Moreover, we numerically compare our method with the conventional distributed algorithms in the case of a data storage system. The numerical results demonstrate the effectiveness and fast convergence of our method.

关键词： acceleration method broadcast optimization algorithm distributed optimization fixed point incremental subgradient method nonexpansive mapping

来源：评论

学校读者我要写书评

暂无评论

Accelerated Restricted Additive Schwarz method for asynchronous processing

引用

RESULTS IN APPLIED MATHEMATICS 2025年 26卷

作者： Ben Bouzid, A. Khali, Y. Khallouq, S. Nagid, N. Univ Moulay Ismail Fac Sci & Tech Lab Math & Interact Meknes Morocco Moulay Ismail Univ Fac Sci Lab Math & Interact Meknes Morocco Univ Cadi Ayyad Fac Sci Semlalia Lab Math Modeling & Automat Syst Marrakech Morocco

This paper examines the parallel efficiency of both synchronous and asynchronous domain decomposition methods (DDMs), when solving algebraic systems derived from the discretization of partial differential equations (PDEs). We consider two separate approaches. First, we use the Restricted Additive Schwarz (RAS) domain decomposition solver as our primary DDM. Second, we integrate an acceleration method to minimize computational costs. For both approaches, we assess the parallel efficiency through various numerical experiments. Our results indicate that the asynchronous method provides a significant improvement in computational speed compared to the synchronous method, especially in large-scale problems. Additionally, the integration of the acceleration method further enhances the performance, reducing the overall computational time.

关键词： Synchronous domain decomposition method Asynchronous domain decomposition method Restricted Additive Schwarz acceleration method

来源：评论

学校读者我要写书评

暂无评论

Adaptive wave-particle decomposition in UGKWP method for high-speed flow simulations

引用

Advances in Aerodynamics 2023年第1期5卷 518-543页

作者： Yufeng Wei Junzhe Cao Xing Ji Kun Xu Department of Mathematics Hong Kong University of Science and TechnologyHong KongChina School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of Environment and Control for Flight Vehicle Xi’an Jiaotong UniversityXi’an710049China Department of Mechanical and Aerospace Engineering Hong Kong University of Science and TechnologyHong KongChina HKUST Shenzhen Research Institute Shenzhen 518057China

With wave-particle decomposition,a unified gas-kinetic wave-particle(UGKWP)method has been developed for multiscale flow *** the variation of the cell Knudsen number,the UGKWP method captures the transport process in all flow regimes without the kinetic solver’s constraint on the numerical mesh size and time step being determined by the kinetic particle mean free path and particle collision *** the current UGKWP method,the cell Knudsen number,which is defined as the ratio of particle collision time to numerical time step,is used to distribute the components in the wave-particle *** adaptation of particles in the UGKWP method is mainly for the capturing of the non-equilibrium *** this aspect,the cell Knudsen number alone is not enough to identify the non-equilibrium *** example,in the equilibrium flow regime with a Maxwellian distribution function,even at a large cell Knudsen number,the flow evolution can be still modelled by the Navier-Stokes *** specifically,in the near space environment both the hypersonic flow around a space vehicle and the plume flow from a satellite nozzle will encounter a far field rarefied equilibrium flow in a large computational *** the background dilute equilibrium region,the large particle collision time and a uniform small numerical time step can result in a large local cell Knudsen number and make the UGKWP method track a huge number of particles for the far field background flow in the original ***,in this region the analytical wave representation can be legitimately used in the UGKWP method to capture the nearly equilibrium flow ***,to further improve the efficiency of the UGKWP method for multiscale flow simulations,an adaptive UGKWP(AUGKWP)method is developed with the introduction of an additional local flow variable gradient-dependent Knudsen *** a result,the wave-particle decomposition in the UGKWP method is determined by both the cell and g

关键词： Adaptive wave-particle decomposition Multiscale modeling acceleration method Non-equilibrium transport

来源：评论

学校读者我要写书评

暂无评论

Accelerated Distributed Optimization Algorithm With Malicious Nodes

引用

IEEE TRANSACTIONS ON NETWORK SCIENCE AND ENGINEERING 2024年第2期11卷 2238-2248页

作者： Zhang, Shiheng Liu, Zhi-Wei Wen, Guanghui Wang, Yan-Wu Huazhong Univ Sci & Technol Sch Artificial Intelligence & Automat Wuhan 430074 Peoples R China Huazhong Univ Sci & Technol Hubei Key Lab Brain inspired Intelligent Syst Wuhan 430074 Peoples R China Southeast Univ Sch Math Dept Syst Sci Nanjing 210096 Peoples R China

This paper addresses the challenges of slow convergence and vulnerability to attacks in distributed optimization for multi-agent systems. To improve the convergence rate in the presence of malicious nodes, a novel algorithm that combines the Mean-Subsequence-Reduce (MSR) method with gradient tracking is proposed. This algorithm enables the local variables of normal agents to converge to a convex combination of locally optimal solutions. However, using the MSR method in distributed optimization can lead to a time-varying transition matrix and the loss of the double stochasticity of the transition matrix, which presents design and analysis challenges. To mitigate this issue, a decreasing factor is introduced to alleviate the accumulation of errors caused by the single-row stochasticity of the transition matrix. We prove that the proposed algorithm achieves consensus and convergence to the point satisfying the optimality conditions. Numerical examples demonstrate the effectiveness of the proposed algorithm, showing a faster convergence rate than existing methods.

关键词： Optimization Convergence Multi-agent systems Stochastic processes Symmetric matrices Linear programming Transforms optimization methods resilient algorithm malicious nodes acceleration 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：