期刊文献+
共找到2,998篇文章
< 1 2 150 >
每页显示 20 50 100
A two-grid algorithm based on Newton iteration for the stream function form of the Navier-Stokes equations 被引量:1
1
作者 SHAO Xin-ping HAN Dan-fu 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2011年第3期368-378,共11页
In this paper, we propose a two-grid algorithm for solving the stream function formulation of the stationary Navies-Stokes equations. The algorithm is constructed by reducing the original system to one small, nonlinea... In this paper, we propose a two-grid algorithm for solving the stream function formulation of the stationary Navies-Stokes equations. The algorithm is constructed by reducing the original system to one small, nonlinear system on the coarse mesh space and two similar linear systems (with same stiffness matrix but different right-hand side) on the fine mesh space. The convergence analysis and error estimation of the algorithm are given for the case of conforming elements. Furthermore, the Mgorithm produces a numerical solution with the optimal asymptotic H^2-error. Finally, we give a numerical illustration to demonstrate the effectiveness of the two-grid algorithm for solving the Navier-Stokes equations. 展开更多
关键词 Two-grid algorithm Navier-Stokes equations Stream function form Reynolds number Newton iteration.
在线阅读 下载PDF
A MULTI-GRID ALGORITHM FOR MIXED PROBLEMS WITH PENALTY BY C°-PIECEWISE LINEAR ELEMENT APPROXIMATION
2
作者 黄自萍 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 1997年第2期121-131,共11页
In this paper we describe a multi-grid algorithm for mixed problems with penalty by the linear finite element approximation. It is proved that the convergence rate of the algorithm is bound ed away from 1 independentl... In this paper we describe a multi-grid algorithm for mixed problems with penalty by the linear finite element approximation. It is proved that the convergence rate of the algorithm is bound ed away from 1 independently of the meshsize. For convenience, we only discuss Jacobi relaxation as smoothing operator in detail. 展开更多
关键词 Multi-grid algorithm MIXED problem problems with PENALTY linear ELEMENT approxi mation.
在线阅读 下载PDF
A Polar Coordinate System Based Grid Algorithm for Star Identification
3
作者 Hua ZHANG Hongshi SANG Xubang SHEN 《Journal of Software Engineering and Applications》 2010年第1期34-38,共5页
In Cartesian coordinate systems, the angular separation-based star identification algorithms involve much trigon- ometric function computing. That delays the algorithm process. As in a polar coordinate system, the coo... In Cartesian coordinate systems, the angular separation-based star identification algorithms involve much trigon- ometric function computing. That delays the algorithm process. As in a polar coordinate system, the coordinates are denoted by angular values, it is potential to speed up the star identification process by adopting a polar coordinate sys-tem. An angular polar coordinate system is introduced and a grid algorithm based on the coordinate system is proposed to enhance the performances of the star identification process. The simulations demonstrate that the algorithm in the angular polar coordinate system is superior to the grid algorithm in the rectangle Cartesian coordinate system in com-puting cost and identification rate. It can be used in the star sensors for high precision and high reliability in spacecraft navigation. 展开更多
关键词 STAR IDENTIFICATION grid algorithm POLAR COORDINATE System STAR SENSOR
在线阅读 下载PDF
The Grid Algorithm of the Development Coefficient and the Combination Coefficient of Background Value in GM(1,1) Model
4
作者 Jianhua Liu Yong Wei 《Journal of Systems Science and Information》 2008年第1期91-96,共6页
This article gives the algorithm of the sector in which the development coefficient is, and the steps to simultaneously calculate the development coefficient and combination coefficient of background value. Unifying t... This article gives the algorithm of the sector in which the development coefficient is, and the steps to simultaneously calculate the development coefficient and combination coefficient of background value. Unifying the development coefficient and the background value's coefficient of combination to optimize the model together, avoiding the malpractice to separate the two in traditional method, and avoiding the error brought out by matrix multiplication because of matrix's illness and so on in the traditional way, therefore increases the precision of the model. 展开更多
关键词 GM(1 1) model development coefficient grid algorithm combination coefficient of background value
原文传递
Multiple QoS modeling and algorithm in computational grid 被引量:1
5
作者 Li Chunlin Feng Meilai Li Layuan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2007年第2期412-417,共6页
Multiple QoS modeling and algorithm in grid system is considered. Grid QoS requirements can be formulated as a utility function for each task as a weighted sum of its each dimensional QoS utility functions. Multiple Q... Multiple QoS modeling and algorithm in grid system is considered. Grid QoS requirements can be formulated as a utility function for each task as a weighted sum of its each dimensional QoS utility functions. Multiple QoS constraint resource scheduling optimization in computational grid is distributed to two subproblems: optimization of grid user and grid resource provider. Grid QoS scheduling can be achieved by solving sub problems via an iterative algorithm. 展开更多
关键词 QoS modeling Computational grid Scheduling algorithm.
在线阅读 下载PDF
Grid-Based Pseudo-Parallel Genetic Algorithm and Its Application 被引量:1
6
作者 陈海英 郭巧 徐力 《Journal of Beijing Institute of Technology》 EI CAS 2006年第1期48-52,共5页
Aimed at the problems of premature and lower convergence of simple genetic algorithms (SGA), three ideas --partition the whole search uniformly, multi-genetic operators and multi-populations evolving independently a... Aimed at the problems of premature and lower convergence of simple genetic algorithms (SGA), three ideas --partition the whole search uniformly, multi-genetic operators and multi-populations evolving independently are introduced, and a grid-based pseudo-parallel genetic algorithms (GPPGA) is put forward. Thereafter, the analysis of premature and convergence of GPPGA is made. In the end, GPPGA is tested by both six-peak camel back function, Rosenbrock function and BP network. The result shows the feasibility and effectiveness of GPPGA in overcoming premature and improving convergence speed and accuracy. 展开更多
关键词 genetic algorithms PARALLEL grid neural network weights optimizing
在线阅读 下载PDF
An efficient algorithm for generating a spherical multiple-cell grid
7
作者 Fang Hou Zhiyi Gao +1 位作者 Jianguo Li Fujiang Yu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2022年第5期41-50,共10页
This paper presents an efficient algorithm for generating a spherical multiple-cell(SMC)grid.The algorithm adopts a recursive loop structure and provides two refinement methods:(1)an arbitrary area refinement method a... This paper presents an efficient algorithm for generating a spherical multiple-cell(SMC)grid.The algorithm adopts a recursive loop structure and provides two refinement methods:(1)an arbitrary area refinement method and(2)a nearshore refinement method.Numerical experiments are carried out,and the results show that compared with the existing grid generation algorithm,this algorithm is more flexible and operable. 展开更多
关键词 spherical multiple-cell grid wave model WAVEWATCH III grid generation algorithm
在线阅读 下载PDF
Sensitivity Encoding Reconstruction for MRI with Gridding Algorithm
8
作者 Lianjun Zhang Gang Liu 《Journal of Computer and Communications》 2021年第2期22-28,共7页
The Sensitivity Encoding (SENSE) parallel reconstruction scheme for magnetic resonance imaging (MRI) is studied and implemented with gridding algorithm in this paper. In this paper, the sensitivity map profile, field ... The Sensitivity Encoding (SENSE) parallel reconstruction scheme for magnetic resonance imaging (MRI) is studied and implemented with gridding algorithm in this paper. In this paper, the sensitivity map profile, field map information and the spiral k-space data collected from an array of receiver coils are used to reconstruct un-aliased images from under-sampled data. The gridding algorithm is implemented with SENSE due to its ability in evaluating forward and adjoins operators with non-Cartesian sampled data. This paper also analyzes the performance of SENSE with real data set and identifies the computational issues that need to be improved for further research. 展开更多
关键词 Parallel Imaging SENSE gridding algorithm
在线阅读 下载PDF
Optimum Tactics of Parallel Multi-Grid Algorithm with Virtual Boundary Forecast Method Running on a Local Network with the PVM Platform 被引量:2
9
作者 郭庆平 章社生 卫加宁 《Journal of Computer Science & Technology》 SCIE EI CSCD 2000年第4期355-359,共5页
In this paper, an optimum tactic of multi-grid parallel algorithmwith virtual boundary forecast method is disscussed, and a two-stage implementationis presented. The numerical results of solving a non-linear heat tran... In this paper, an optimum tactic of multi-grid parallel algorithmwith virtual boundary forecast method is disscussed, and a two-stage implementationis presented. The numerical results of solving a non-linear heat transfer equationshow that the optimum implementation is much better than the non-optimum one. 展开更多
关键词 algorithm parallel multi-grid virtual boundary forecast (VBF) speedup network computing PVM
原文传递
Harmonic Suppression Method Based on Immune Particle Swarm Optimization Algorithm in Micro-Grid 被引量:1
10
作者 Ying Zhang Yufeng Gong +1 位作者 Junyu Chen Jing Wang 《Journal of Power and Energy Engineering》 2014年第4期271-279,共9页
Distributed generation has attracted great attention in recent years, thanks to the progress in new-generation technologies and advanced power electronics. And micro-grid can make full use of distributed generation, s... Distributed generation has attracted great attention in recent years, thanks to the progress in new-generation technologies and advanced power electronics. And micro-grid can make full use of distributed generation, so it has been widespread concern. On the other hand due to the extensive use of power electronic devices and many of the loads within micro-grid are nonlinear in nature, Micro-grid generate a large number of harmonics, so harmonics pollution needs to be addressed. Usually we use passive filter to filter out harmonic, in this paper, we propose a new method to optimize the filter parameters, so passive filter can filter out harmonic better. This method utilizes immune particle swarm optimization algorithm to optimize filter parameters. It can be shown from the simulation results that the proposed method is effective for micro-grid voltage harmonics compensation. 展开更多
关键词 MICRO-grid IMMUNE PARTICLE SWARM Optimization algorithm HARMONIC COMPENSATION
在线阅读 下载PDF
Predictive direct power control of three-phase PWM rectifier based on TOGI grid voltage sensor free algorithm
11
作者 ZHAO Feng LI Shute +4 位作者 CHEN Xiaoqiang WANG Ying GAN Yanqi NIU Xinqiang ZHANG Fan 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2022年第4期451-459,共9页
In predictive direct power control(PDPC)system of three-phase pulse width modulation(PWM)rectifier,grid voltage sensor makes the whole system more complex and costly.Therefore,third-order generalized integrator(TOGI)i... In predictive direct power control(PDPC)system of three-phase pulse width modulation(PWM)rectifier,grid voltage sensor makes the whole system more complex and costly.Therefore,third-order generalized integrator(TOGI)is used to generate orthogonal signals with the same frequency to estimate the grid voltage.In addition,in view of the deviation between actual and reference power in the three-phase PWM rectifier traditional PDPC strategy,a power correction link is designed to correct the power reference value.The grid voltage sensor free algorithm based on TOGI and the corrected PDPC strategy are applied to three-phase PWM rectifier and simulated on the simulation platform.Simulation results show that the proposed method can effectively eliminate the power tracking deviation and the grid voltage.The effectiveness of the proposed method is verified by comparing the simulation results. 展开更多
关键词 three-phase PWM rectifier predictive direct power control grid voltage sensor free algorithm third-order generalized integrator power correction
在线阅读 下载PDF
Grid-Based Path Planner Using Multivariant Optimization Algorithm
12
作者 Baolei Li Danjv Lv +3 位作者 Xinling Shi Zhenzhou An Yufeng Zhang Jianhua Chen 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2015年第5期89-96,共8页
To solve the shortest path planning problems on grid-based map efficiently,a novel heuristic path planning approach based on an intelligent swarm optimization method called Multivariant Optimization Algorithm( MOA) an... To solve the shortest path planning problems on grid-based map efficiently,a novel heuristic path planning approach based on an intelligent swarm optimization method called Multivariant Optimization Algorithm( MOA) and a modified indirect encoding scheme are proposed. In MOA,the solution space is iteratively searched through global exploration and local exploitation by intelligent searching individuals,who are named as atoms. MOA is employed to locate the shortest path through iterations of global path planning and local path refinements in the proposed path planning approach. In each iteration,a group of global atoms are employed to perform the global path planning aiming at finding some candidate paths rapidly and then a group of local atoms are allotted to each candidate path for refinement. Further,the traditional indirect encoding scheme is modified to reduce the possibility of constructing an infeasible path from an array. Comparative experiments against two other frequently use intelligent optimization approaches: Genetic Algorithm( GA) and Particle Swarm Optimization( PSO) are conducted on benchmark test problems of varying complexity to evaluate the performance of MOA. The results demonstrate that MOA outperforms GA and PSO in terms of optimality indicated by the length of the located path. 展开更多
关键词 multivariant optimization algorithm shortest path planning heuristic search grid map optimality of algorithm
在线阅读 下载PDF
A novel decomposition and coordination algorithm for complex networks and its application to power grids 被引量:3
13
作者 Xiangping NI Shengwei MEI 《控制理论与应用(英文版)》 EI 2008年第1期53-58,共6页
To analyze and control complex networks effectively, this paper puts forward a new kind of scheme, which takes control separately in each area and can achieve the network’s coordinated optimality. The proposed algori... To analyze and control complex networks effectively, this paper puts forward a new kind of scheme, which takes control separately in each area and can achieve the network’s coordinated optimality. The proposed algorithm is made up of two parts: the first part decomposes the network into several independent areas based on community structure and decouples the information flow and control power among areas; the second part selects the center nodes from each area with the help of the control centrality index. As long as the status of center nodes is kept on a satisfactory level in each area, the whole system is under effective control. Finally, the algorithm is applied to power grids, and the simulations prove its effectiveness. 展开更多
关键词 复杂网络 网络结构 调和算法 电力网络
在线阅读 下载PDF
Nearest neighbor search algorithm based on multiple background grids for fluid simulation 被引量:2
14
作者 郑德群 武频 +1 位作者 尚伟烈 曹啸鹏 《Journal of Shanghai University(English Edition)》 CAS 2011年第5期405-408,共4页
The core of smoothed particle hydrodynamics (SPH) is the nearest neighbor search subroutine. In this paper, a nearest neighbor search algorithm which is based on multiple background grids and support variable smooth... The core of smoothed particle hydrodynamics (SPH) is the nearest neighbor search subroutine. In this paper, a nearest neighbor search algorithm which is based on multiple background grids and support variable smooth length is introduced. Through tested on lid driven cavity flow, it is clear that this method can provide high accuracy. Analysis and experiments have been made on its parallelism, and the results show that this method has better parallelism and with adding processors its accuracy become higher, thus it achieves that efficiency grows in pace with accuracy. 展开更多
关键词 multiple background grids smoothed particle hydrodynamics (SPH) nearest neighbor search algorithm parallel computing
在线阅读 下载PDF
Impact of the Objective Function on the Construction of Internal Grids of Wind Farms Using Genetic Algorithm
15
作者 Paulo R. Monteiro Duailibe Thiago T. Borges +1 位作者 André F. Schiochet Carlos Alberto P. Soares 《Open Journal of Civil Engineering》 2016年第5期705-721,共18页
The macro complex of the construction industry is energy intensive. Solutions that enable the supply of this demand while meeting the principles of sustainability are needed. The construction of wind farms has been a ... The macro complex of the construction industry is energy intensive. Solutions that enable the supply of this demand while meeting the principles of sustainability are needed. The construction of wind farms has been a strategy employed by many countries to produce clean energy. An increase in the construction of wind farms has also been witnessed in Brazil. This calls for different activities, such as the design and construction of infrastructure. This article focuses on the design of internal medium voltage distribution grids for wind farms. The purpose is to find a radial configuration that connects a set of wind generators to the substation, in an optimum way, minimizing operational and construction costs, reducing loss and therefore contributing to sustainability. In large farms, the project design consists of a large combinatorial optimization problem, given the large number of possible configurations to be deployed. Finding the best solution for the internal grid depends on the criterion adopted for the objectives pursued. This article analyzes the different criteria that can be adopted in the design of the wind farm’s internal grid using a methodology based on genetic algorithm (GA). Its aim is to identify their influence on the solution of the problem and help decision-making by finding the most adequate criterion for the objectives pursued. The results show that the design of the internal grid is sensitive to the criteria adopted for the objective function. In addition, the degree of sensitivity is analyzed, showing that, in some cases, the solutions are not economically attractive and do not contribute to the reduction of losses. 展开更多
关键词 Construction Infrastructure Wind Farm Infrastructure Collection grid Network Configuration Genetic algorithm
在线阅读 下载PDF
An Improved Task Scheduling Algorithm in Grid Computing Environment
16
作者 Liang Yu Gang Zhou Yifei Pu 《International Journal of Communications, Network and System Sciences》 2011年第4期227-231,共5页
Algorithm research of task scheduling is one of the key techniques in grid computing. This paper firstly describes a DAG task scheduling model used in grid computing environment, secondly discusses generational schedu... Algorithm research of task scheduling is one of the key techniques in grid computing. This paper firstly describes a DAG task scheduling model used in grid computing environment, secondly discusses generational scheduling (GS) and communication inclusion generational scheduling (CIGS) algorithms. Finally, an improved CIGS algorithm is proposed to use in grid computing environment, and it has been proved effectively. 展开更多
关键词 grid COMPUTING Model of TASK SCHEDULING HEURISTICS algorithm Dependent TASK SCHEDULING algorithm
在线阅读 下载PDF
Performance Analysis of Grid Based AODV Routing Algorithm for AD Hoc Wireless Networks
17
作者 Abderezak Touzene Ishaq Al-Yahyai 《International Journal of Communications, Network and System Sciences》 2015年第13期523-532,共10页
In many traditional On Demand routing algorithms in Ad hoc wireless networks, a simple flooding mechanism is used to broadcast route request (RREQ) packets when there is a need to establish a route from a source node ... In many traditional On Demand routing algorithms in Ad hoc wireless networks, a simple flooding mechanism is used to broadcast route request (RREQ) packets when there is a need to establish a route from a source node to a destination node. The broadcast of RREQ may lead to high channel contention, high packet collisions, and thus high delay to establish the routes, especially with high density networks. Ad hoc on Demand Distance Vector Routing Protocol (AODV) is one among the most effective Reactive Routing Protocols in MANETs which use simple flooding mechanism to broadcast the RREQ. It is also used in Wireless Sensor Networks (WSN) and in Vehicular Ad hoc Networks (VANET). This paper proposes a new modified AODV routing protocol EGBB-AODV where the RREQ mechanism is using a grid based broadcast (EGBB) which reduces considerably the number of rebroadcast of RREQ packets, and hence improves the performance of the routing protocol. We developed a simulation model based on NS2 simulator to measure the performance of EGBB-AODV and compare the results to the original AODV and a position-aware improved counter-based algorithm (PCB-AODV). The simulation experiments that EGBB-AODV outperforms AODV and PCB-AODV in terms of end-to-end delay, delivery ratio and power consumption, under different traffic load, and network density conditions. 展开更多
关键词 Mobile AD-HOC Networks AODV ROUTING algorithm Position-Based ROUTING grid-Based ROUTING NS2
在线阅读 下载PDF
基于网格归一化Astar算法的船舶管路布置
18
作者 林焰 张乔宇 楼建迪 《上海交通大学学报》 北大核心 2025年第1期79-88,共10页
为解决船舶管路布置方法中目前存在的依靠人工经验调节算法参数,权重系数的设置量级差距较大,以及求解布置方案单一的问题,提出一种网格归一化Astar (GNAstar)的布置方法.首先,采用包围盒和网格法建立数学模型.其次,通过分支管路拆分、... 为解决船舶管路布置方法中目前存在的依靠人工经验调节算法参数,权重系数的设置量级差距较大,以及求解布置方案单一的问题,提出一种网格归一化Astar (GNAstar)的布置方法.首先,采用包围盒和网格法建立数学模型.其次,通过分支管路拆分、网格标记值和父子网格搜索策略,使每一路径节点由不同目标的归一化权重值来共同决定,将传统Astar算法仅考虑长度的目标扩展成包括长度、弯头消耗和安装适用性的管路综合布置目标.最后,通过仿真案例将GNAstar算法与传统Astar算法进行对比分析,并以船舶机舱内不同管路系统为例,与文献中的蚁群算法和粒子群-Astar算法开展进一步比较.结果表明,GNAstar算法可获得有效的工程解,设计人员可通过设置不同目标的归一化权重系数来获得相应的布置方案. 展开更多
关键词 船舶管路 布置优化 Astar算法 网格归一化
在线阅读 下载PDF
三轴稳定型静止轨道遥感卫星地理定位快速算法
19
作者 李贺 童晓冲 +2 位作者 章程 王智超 李树林 《测绘科学技术学报》 2025年第1期37-41,48,共6页
三轴稳定型静止轨道遥感卫星具有高时间分辨率的特点,在气象预报、环境监测等领域发挥着重要作用。通过分析静止轨道遥感卫星常规地理定位方法和国际气象卫星协调组织CGMS(Coordination Group for Meteorological Satellites)标称网格... 三轴稳定型静止轨道遥感卫星具有高时间分辨率的特点,在气象预报、环境监测等领域发挥着重要作用。通过分析静止轨道遥感卫星常规地理定位方法和国际气象卫星协调组织CGMS(Coordination Group for Meteorological Satellites)标称网格发布格式,提出一种针对三轴稳定型静止轨道遥感卫星图像地理定位的快速算法。首先,构建传感器各个探元的初始入射视向量;随后,经卫星平台东西镜和南北镜反射,得到载荷坐标系下的出射向量;最后将该向量转换到卫星本体坐标系,且依次经过卫星轨道坐标系和地固坐标系的转换,得到理想情况下的CGMS标称网格下的镜子转角,该镜子转角即可转换到唯一对应的CGMS标称网格位置,完成数据的定位。该算法省略了光线视向量从地固坐标系出发与大地椭球面求交点计算的复杂过程,在不损失定位精度的情况下,时效性能较常规地理定位方法提升了83.3%。 展开更多
关键词 三轴稳定 静止轨道 遥感卫星 标称网格 地理定位快速算法
在线阅读 下载PDF
基于Rao算法的CEP最优潮流调度模型研究
20
作者 赵化时 周华锋 +3 位作者 李文朝 何宇斌 阮光宗 崔旭东 《电子器件》 2025年第1期200-205,共6页
为推进数字化转型战略落地,云边融合智能调度运行平台(CEP)应运而生。同时,为了满足负荷需求和运行限制,实现智能调度具有迫切的必要性。基于Rao(Cramér-Rao Lower Bound)算法提出了一种新的潮流调度模型。首先,考虑新型并网主体... 为推进数字化转型战略落地,云边融合智能调度运行平台(CEP)应运而生。同时,为了满足负荷需求和运行限制,实现智能调度具有迫切的必要性。基于Rao(Cramér-Rao Lower Bound)算法提出了一种新的潮流调度模型。首先,考虑新型并网主体的特性,根据约束条件与目标函数构建出潮流调度模型。其次,构建并介绍了云端系统平台,其具备数据存储、计算能力和分布式计算资源,为优化算法提供了强大的支持和基础,同时,将Rao算法应用于潮流计算之中,根据最优解与最劣解之间的交互关系设计出相应程序。最后,在IEEE 30节点系统上进行了建模,同时将所提出的算法输入CEP调度平台进行试验,将结果与现有的优化方法进行了比较。结果表明,所提出的策略具有很好的收敛特性,与目标函数的适应度最强,其能够在保持高精度的同时避免过早陷入局部最优解。因此所提出的模型和方法能为CEP平台的构建提供稳定高效的调度优化方案。 展开更多
关键词 云边融合智能调度运行平台 Rao算法 电网调度 潮流计算
在线阅读 下载PDF
上一页 1 2 150 下一页 到第
使用帮助 返回顶部