Effective loading algorithm associated with explicit dynamic relaxation method for simulating static problems

Based on the fact that a static problem has an equivalent wave speed of infinity and a dynamic problem has a wave speed of finite value, an effective loading algorithm associated with the explicit dynamic relaxation method was presented to produce meaningful numerical solutions for static problems. The central part of the explicit dynamic relaxation method is to turn a time-independent static problem into an artificial time-dependent dynamic problem. The related numerical testing results demonstrate that: (1) the proposed effective loading algorithm is capable of enabling an applied load in a static problem to be propagated throughout the whole system within a given loading increment, so that the time-independent solution of the static problem can be obtained; (2) the proposed effective loading algorithm can be straightforwardly applied to the particle simulation method for solving a wide range of static problems.

ANALYSIS OF WAVEGUIDE PROBLEMS USING A RELAXED ITERATIVE DOMAIN DECOMPOSITION METHOD COMBINED WITH MULTIFRONTAL ALGORITHM

In this paper, an absorbing Fictitious Boundary Condition (FBC) is presented to generate an iterative Domain Decomposition Method (DDM) for analyzing waveguide problems.The relaxed algorithm is introduced to improve the iterative convergence. And the matrix equations are solved using the multifrontal algorithm. The resulting CPU time is greatly reduced.Finally, a number of numerical examples are given to illustrate its accuracy and efficiency.

Concise review of relaxations and approximation algorithms for nonidentical parallel-machine scheduling to minimize total weighted completion times

A class of nonidentical parallel machine scheduling problems are considered in which the goal is to minimize the total weighted completion time.Models and relaxations are collected.Most of these problems are NP-hard,in the strong sense,or open problems,therefore approximation algorithms are studied.The review reveals that there exist some potential areas worthy of further research.

On the Relaxation Parameters of MQ-Algorithm

In this paper, a new method, so called A-method, is given for the convergence analysis of the MQ-algorithm. And the finer relaxation parameter θA is obtained. The numerical results show that our new method has the outstanding effect of accelerating convergence. Moreover, the relaxation parameter θA is the optimum in a point of view.

CONVERGENCE RESULTS FOR NON-OVERLAP SCHWARZ WAVEFORM RELAXATION ALGORITHM WITH CHANGING TRANSMISSION CONDITIONS

In this paper,we establish a new algorithm to the non-overlapping Schwarz domain decomposition methods with changing transmission conditions for solving one dimensional advection reaction diffusion problem.More precisely,we first describe the new algorithm and prove the convergence results under several natural assumptions on the sequences of parameters which determine the transmission conditions.Then we give a simple method to estimate the new value of parameters in each iteration.The interesting advantage of our method is that one may update the better parameters in each iteration to save the computational cost for optimizing the parameters after many steps.Finally some numerical experiments are performed to show the behavior of the convergence rate for the new method.

Discretized Multisplitting AOR Waveform Relaxation Algorithms for Initial Value Problem of Systems of ODEs

The multisplitting algorithm for solving large systems of ordinary differential equations on parallel computers was introduced by Jeltsch and Pohl in [1]. On fixed time intervals conver gence results could be derived if the subsystems are solving exactly.Firstly,in theis paper,we deal with an extension of the waveform relaxation algorithm by us ing multisplittin AOR method based on an overlapping block decomposition. We restricted our selves to equidistant timepoints and dealed with the case that an implicit integration method was used to solve the subsystems numerically in parallel. Then we have proved convergence of multi splitting AOR waveform relaxation algorithm on a fixed window containing a finite number of timepoints.

SEMI-DEFINITE RELAXATION ALGORITHM OF MULTIPLE KNAPSACK PROBLEM

The multiple knapsack problem denoted by MKP (B,S,m,n) can be defined as fol- lows.A set B of n items and a set Sof m knapsacks are given such thateach item j has a profit pjand weightwj,and each knapsack i has a capacity Ci.The goal is to find a subset of items of maximum profit such that they have a feasible packing in the knapsacks.MKP(B,S,m,n) is strongly NP- Complete and no polynomial- time approximation algorithm can have an approxima- tion ratio better than0 .5 .In the last ten years,semi- definite programming has been empolyed to solve some combinatorial problems successfully.This paper firstly presents a semi- definite re- laxation algorithm (MKPS) for MKP (B,S,m,n) .It is proved that MKPS have a approxima- tion ratio better than 0 .5 for a subclass of MKP (B,S,m,n) with n≤ 1 0 0 ,m≤ 5 and maxnj=1{ wj} minmi=1{ Ci} ≤ 2 3 .

On Over-Relaxed Proximal Point Algorithms for Generalized Nonlinear Operator Equation with (A,η,m)-Monotonicity Framework

In this paper, a new class of over-relaxed proximal point algorithms for solving nonlinear operator equations with (A,η,m)-monotonicity framework in Hilbert spaces is introduced and studied. Further, by using the generalized resolvent operator technique associated with the (A,η,m)-monotone operators, the approximation solvability of the operator equation problems and the convergence of iterative sequences generated by the algorithm are discussed. Our results improve and generalize the corresponding results in the literature.

Relaxation-strategy-based Modification Branch-and-Bound Algorithm for Solving a Class of Transportation-production Problems

In this paper,a new algorithm relaxation-strategy-based modification branchand-bound algorithm is developed for a type of solving the minimum cost transportationproduction problem with concave production costs.The major improvement of the proposed new method is that modification algorithm reinforces the bounding operation using a Lagrangian relaxation,which is a concave minimization but obtains a tighter bound than the usual linear programming relaxation.Some computational results are included.Computation results indicate that the algorithm can solve fairly large scale problems.

基于RELAX频谱分析方法的鼠笼式异步电动机转子故障诊断

在基于电流信号分析的异步电机故障诊断方法中,故障特征成分(尤其是断条特征)往往容易被基波分量和噪声信号中所淹没。因此,有效地克服基波和噪声的影响是诊断过程的关键。RELAX是一种对加性噪声以及系统误差假设可松弛的算法,提出了一种基于该算法的鼠笼式异步电动机转子故障监测与诊断方法。文中从理论上推导了鼠笼式异步电动机转子故障时的电流信号模型,将RELAX算法应用于电源基波特征参数提取,并从噪声和杂波的连续谱中估计出特定故障的离散谱参数,从而达到消除电源和噪声影响、突出故障特征的目的。通过对样机实测信号进行了分析处理,实验结果验证了RELAX算法的有效性和优越性。

基于Relax散射点特征提取的舰船目标识别方法

针对基于高分辨距离像(HRRP)的舰船目标识别问题,提出了一种基于Relax散射点特征提取和设计了基于散射中心最近邻模糊分类器的目标识别方法。首先对数据进行预处理,然后基于Relax算法提取出散射中心,最后通过最近邻模糊分类器进行识别匹配。通过仿真4类军民船目标的数据进行测试,验证结果表明该方法在舰船目标识别领域具有很好的应用前景。

采用RELAX算法提高单脉冲三维成像横向分辨率

根据宽带比相单脉冲三维成像雷达测量目标散射点横向位置原理,分析仿真了散射点间相互干扰对目标散射点横向位置测量的影响。应用RELAX算法直接估计去斜率后正弦信号的幅度和频率参数,提高散射点横向位置测量精度。通过分析及仿真可知,RELAX算法的引入使横向位置测量精度有了较明显改善。

基于TEASER算法的空间非合作目标位姿估计

基于点云的空间非合作目标位姿估计,常受到噪声影响.提出截断最小二乘估计与半定松弛(truncated least squares estimation and semidefinite relaxation,TEASER)与迭代最近点(iterative closest point,ICP)的结合算法,提升空间非合作目标位姿估计精度与鲁棒性.该方法包括粗配准与精配准两个环节:在粗配准环节中,基于局部点云与模型点云的方向直方图特征(signature of histogram of orientation,SHOT)确定匹配对,利用TEASER算法求解初始位姿;在精配准环节中,可结合ICP算法优化位姿估计结果.北斗卫星仿真实验表明:在连续帧位姿估计中,噪声标准差为3倍点云分辨率时,基于TEASER的周期关键帧配准方法的平移误差小于3.33 cm,旋转误差小于2.18°;与传统ICP方法相比,平均平移误差与平均旋转误差均有所降低.这表明所提出的空间非合作目标位姿估计方法具有良好的精度和鲁棒性.

高分辨雷达目标的RELAX与MRELAX参数特征

用 REL AX算法和改进的 MREL AX算法对实测雷达数据分别进行处理 ,从高分辨雷达回波距离像中提取目标特征参数并进行比较分析 .仿真实验证明 ,用 MREL AX算法对高分辨雷达目标数据进行处理与用 REL AX算法处理的结果比较 ,MREL AX算法得到了更加清晰的目标特征 .

RELAX参数估计算法在雷达目标特征提取中的应用

从理论上推导分析了聚束式SAR(SpotlightSAR)的chirp信号回波模型。在回波模型中,回波被分解为两部分——强散射点的回波信号以及噪声和杂波,强散射点的回波(正弦信号)为离散谱,而噪声和杂波为连续谱。基于该回波模型,将RELAX算法应用于对可分解为若干强散射点的特定目标的特征提取,从噪声和杂波的连续谱中估计出强散射点回波的离散谱参数,频率对应于强散射点的位置、幅值对应于强散射点的RCS,从而实现对目标的特征提取。最后,通过计算机仿真,验证RELAX算法的有效性和优越性。

RELAX算法在间谐波检测中的应用

间谐波是频率非基波整数倍的谐波成分,传统谐波测量方法将会因为非同步采样而产生泄漏误差。为准确测量间谐波,文中提出基于松弛谱估计(RELAX)的检测方法。因为该方法针对复信号进行分析,在检测前需先对采样信号进行希尔伯特变换构成复序列,计算结束后的相位测量结果也要进行修正。由于RELAX算法的复杂度集中在快速傅里叶变换(FFT)处,故相比于其它方法其计算速度是有优势的。最后通过对具体间谐波信号的仿真测量,验证了该方法的有效性和实用性。

基于RELAX算法的飞机油耗性能估计方法

飞机油耗性能直接关系到航空公司的运力调配与盈利程度。根据飞机实际飞行数据,建立了指数衰减型的飞机油耗性能模型。基于油耗性能函数中各分量随飞行距离衰减速度不同的特性,引入数据非一致性检测中的广义内积算法和RELAX信号分离迭代算法,实现油耗性能函数各分量的分离和参数估计。CRB分析验证了参数估计算法的性能;A330飞机的飞行数据实验结果验证了指数衰减型油耗性能模型和参数估计方法的有效性。该方法为运输飞机油耗性能评估提供了一种参考准则。

RELAX算法在鼠笼式异步电机转子故障诊断中的应用

以煤矿用来通风的鼠笼式异步电机为研究对象,针对利用定子电流信号来诊断电动机转子故障时,断条故障特征频率成分容易被电流基频分量淹没而无法准确检测的实际情况,设计了一种基于RELAX算法以剔除定子电流基波频率分量,达到提取转子断条故障特征频率成分的方法。实验结果表明:RELAX算法能有效地剔除定子电流信号中的基波分量,分离出故障特征分量,具有较高的实用价值。

RELAX算法的分辨特性分析

本文讨论了RELAX算法实现信号分离的数学机理以及实现信号分辨的一些特性,探讨了这些特性对其实现信号分辨与否的表现;而且对从DD-RELAX到CD-RELAX、ELAX-AS以及MD-RELAX的发展和联系作了分析讨论。最后对所作理论分析进行了计算机模拟。

求解分裂可行问题的次梯度投影松弛算法

在无限维Hilbert空间中,区别于现有许多算法中的正交投影,采用次梯度投影法,提出求解分裂可行问题的次梯度投影松弛算法,并利用次梯度算子的cutter性质以及分类讨论的思想,证明了次梯度投影松弛算法生成的序列弱收敛于分裂可行问题的解.