位置加权的改进粒子群算法

针对基本粒子群算法具有后期收敛速度慢、容易陷入局部极值等缺陷,通过考虑粒子的位置之间的加权作用,对基本粒子群算法进行了改进,提出了一种位置加权的粒子群算法以减小搜索过程中的盲目性。测试函数结果表明,算法的收敛性以及收敛速度与粒子群算法位置加权因子有很大关系,通过选择合适的加权因子能有效提高算法的计算效率,算法适用于地球物理优化领域的波动方程反问题。     

一类新的粒子群算法

提出一种新的模糊粒子群优化算法--收敛模糊粒子群优化算法.重点研究了收敛因子的确定和模糊隶属度函数的选择对算法性能的影响,在考虑计算效率的同时,提高了算法的精度.利用4个基准函数测试了收敛模糊粒子群优化算法的性能,并与模糊粒子群优化算法、收敛粒子群优化算法以及基本粒子群优化算法进行了对比.实验结果表明,新算法具有很好的性能.     

一类新的粒子群算法

提出一种新的模糊粒子群优化算法---收敛模糊粒子群优化算法.重点研究了收敛因子的确定和模糊隶属度函数的选择对算法性能的影响.在考虑计算效率的同时,提高了算法的精度.利用4个基准函数测试了收敛模糊粒子群优化算法的性能,并与模糊粒子群优化算法$收敛粒子群优化算法以及基本粒子群优化算法进行了对比.实验结果表明#新算法具有很好的性能.

     

一种基于加权有向拓扑的改进粒子群算法

研究粒子群优化算法(PSO)的拓扑结构和信息流动,以提高算法性能是PSO的一个有意义的研究方向。RuiMendes等人提出的全联通型算法(FIPSO),其拓扑结构本质上是加权无向图,两个邻接点之间的相互影响是对等的,与社会人际网络的真实情况不符。提出了一种改进型算法,重新构造了加权函数,体现了粒子之间影响的不平衡性。仿真结果显示:该改进算法对收敛速度和稳定性均有非常好的改善。     

一种双层可变子群的动态粒子群优化算法

粒子间信息的共享方式对粒子群优化算法的收敛速度和全局搜索能力有重要的影响.针对全互联、环形拓扑结构,提出基于双层子群的信息共享方式,以收敛率作为子群规模变化的标识,实现子群规模动态变化,协调了算法的全局搜索能力和局部寻优能力.子群排斥机制使子群跳出局部最优解的束缚,提高解的多样性.选取目前比较流行的几种粒子群优化算法,通过五种经典的Benchmark高维函数优化问题进行实验仿真.结果表明基于双层可变子群的动态粒子群优化算法可以有效的避免算法陷入局部最优,在保证收敛速度的同时算法的全局搜索能力和精度有明显的提高.     

一种基于竞争策略的粒子群优化算法

为提高粒子群优化(Particle Swarm optimization,PSO)算法的收敛精精度与速度,提出了一种基于竞争策略的粒子群优化算法.算法通过对两粒子相似度的判定,来决定是否对粒子进行变换操作,能够提高粒子的多样性,避免局部最优,提高了收敛精度,片且当两个粒子被判定为同一个粒子时,根据适者生存的思想,适应度较优的粒子保留下来,适应度较差的粒子则需进行高斯变异变换,在保证粒子多样性的基础上减少了运算量,提高了收敛速度.并且通过多峰函数(Achley函数、Schaffer函数、Grienwank函数)验证,结果表明,改进后的粒子群优化算法在收敛精度与收敛速度方面都优于基本的粒子群优化算法.     

基于RMSprop的粒子群优化算法

粒子群算法对所有粒子采用相同的惯性权重,忽视了单个粒子的特性,导致收敛精度偏低且易陷入局部最优.结合RMSprop算法中对每一个维度进行自适应设置的策略,提出一种自适应惯性权重粒子群优化算法RMSPSO.考虑粒子每一个维度的速度变化及动量,进行自适应动态惯性权重设置,使算法在全局寻优和局部寻优之间达到良好平衡.选取10个典型测试函数,将改进后的粒子群算法(RMSPSO)与4个主流粒子群算法进行实验对比分析,实验结果表明,在单峰、多峰和组合函数上,RMSPSO算法在收敛速度和收敛精度上取得了明显进步.     

基于动态维度交叉的粒子群高维函数优化

提出一种优化高维函数的改进粒子群算法.粒子群算法在高维函数优化方面精度比较低,种群容易陷入停滞,分析粒子群算法在针对高维函数方面难以优化的原因,提出一种基于动态维度交又的改进粒子群算法,通过对五个典型测试函数的仿真,说明该算法具有摆脱较快的收敛能力和较高的收敛精度.     

一种基于加权有向拓扑的改进粒子群算法

研究粒子群优化算法（PSO）的拓扑结构和信息流动，以提高算法性能是PSO的一个有意义的研究方向。RuiMendes等人提出的全联通型算法（FIPSO），其拓扑结构本质上是加权无向图，两个邻接点之间的相互影响是对等的，与社会人际网络的真实情况不符。提出了一种改进型算法，重新构造了加权函数，体现了粒子之间影响的不平衡性。仿真结果显示：该改进算法对收敛速度和稳定性均有非常好的改善。     

一类非线性极小极大问题的粒子群-邻近点算法

针对每个分量函数都是凸函数的离散型非线性极小极大问题,提出一种全局收敛的粒子群-邻近点混合算法。该算法利用极大熵函数将极小极大问题转化为一个光滑函数的无约束凸优化问题;利用邻近点算法为外层算法,内层算法采用粒子群算法来优化此问题;数值结果表明,该算法数值稳定性好、收敛快,是求解此类非线性极小极大问题的一种有效算法。     

基于麦克风阵列的GCC时延估计算法分析

准确的时延估计（Time Delay Estimation,TDE）是基于到达时间差（Time Difference of Arrival,TDOA）的声源定位技术的前提.在众多时延估计算法中,广义互相关（Generalized Cross Correlation,GCC）算法因其较低的运算复杂度和易于实现的特点得到了广泛的应用.针对不同的噪声情况,GCC时延估计算法利用不同的加权函数来抑制噪声干扰.本文在介绍麦克风阵列模型和GCC时延估计算法的基础上,针对GCC算法的弊端提出了一种改进算法,并在多种信噪比条件下,对部分加权函数的GCC时延估计算法进行了MATLAB仿真,通过比较其时延估计性能和声源定位精度,分析了这些加权函数各自的优劣性.     

Specular Lobe‐Aware Filtering and Upsampling for Interactive Indirect Illumination

Although geometry‐aware filtering and upsampling have often been used for interactive or real‐time rendering, they are unsuitable for glossy surfaces because shading results strongly depend on the bidirectional reflectance distribution functions. This paper proposes a novel weighting function of cross bilateral filtering and upsampling to measure the similarity of specular lobes. The difficulty is that a specular lobe is represented with a distribution function in directional space, whereas conventional cross bilateral filtering evaluates similarities using the distance between two points in a Euclidean space. Therefore, this paper first generalizes cross bilateral filtering for the similarity of distribution functions in a non‐Euclidean space. Then, the weighting function is specialized for specular lobes. Our key insight is that the weighting function of bilateral filtering can be represented with the product integral of two distribution functions corresponding to two pixels. In addition, we propose spherical Gaussian‐based approximations to calculate this weighting function analytically. Our weighting function detects the edges of glossiness, and adapts to all‐frequency materials using only a camera position and G‐buffer. These features are not only suitable for path tracing, but also deferred shading and non‐ray tracing–based methods such as voxel cone tracing.     

Adaptive Variational Method for Restoring Color Images with High Density Impulse Noise

In this paper, a new variational framework of restoring color images with impulse noise is presented. The novelty of this work is the introduction of an adaptively weighting data-fidelity term in the cost functional. The fidelity term is derived from statistical methods and contains two weighting functions as well as some statistical control parameters of noise. This method is based on the fact that impulse noise can be approximated as an additive noise with probability density function (PDF) being the finite mixture model. A Bayesian framework is then formulated in which likelihood functions are given by the mixture model. Inspired by the expectation-maximization (EM) algorithm, we present two models with variational framework in this study. The superiority of the proposed models is that: the weighting functions can effectively detect the noise in the image; with the noise information, the proposed algorithm can automatically balance the regularity of the restored image and the fidelity term by updating the weighting functions and the control parameters. These two steps ensure that one can obtain a good restoration even though the degraded color image is contaminated by impulse noise with large ration (90% or more). In addition, the numerical implementation of this algorithm is very fast by using a split algorithm. Some numerical experimental results and comparisons with other methods are provided to show the significant effectiveness of our approach.     

基于MOGA算法的??∞ 回路成形直升机姿态控制器设计

提出一种改进的显模型跟踪??∞回路成形控制方法, 利用??_∞ 回路成形算法补偿显模型跟踪算法中前馈模型逆的不确定性. 针对??_∞ 回路成形控制算法中权重函数选取的盲目性, 利用多目标遗传算法, 结合改进的小生境淘汰技术对权重函数进行寻优, 以提高设计效率和准确性. 基于所提出的方法设计直升机的内回路显模型跟踪??∞ 回路成形姿态控制系统, 能够提高系统的鲁棒性.

     

具有可变性能指标的自校正自适应控制理论的研究

本文在广义最小方差基础上提出了具有可变性能指标函数的自校正控制方案,依据所要 求的特征方程之根在线地改变权函数来确定控制律.本方案控制的算法不仅简单而且容易 实现.计算机模拟仿真结果表明此控制律性能优于一般的自校正控制律,最终利用本文的方 案对船舶航向实施自校正控制进行了讨论并实现了在"大明山"号轮船上的实际海试,结果表 明性能优良.     

无线传感器网络节点的非视距定位方案研究

在无线传感器网络定位中,节点精确定位面临的一个主要问题是信号的非视距传播,非视距误差是节点定位误差的主要来源。在分析非视距误差抑制技术的基础上,提出了一种新的残差加权定位算法。算法通过逐步减少距离测量值个数的组合方式,在每一步选取残差最小的组合,再用加权平均的方法,并利用改进的最小二乘法计算节点临时坐标。仿真结果表明,算法具有较高的定位精度,在不同的非视距误差下表现稳定。     

基于多特征模糊聚类的图像融合方法

首先利用模糊C-均值聚类算法在多特征形成的特征空间上对图像进行区域分割,并在此基础上对区域进行多尺度小波分解;然后利用柯西函数构造区域的模糊相似度,应用模糊相似度及区域信息量构造加权因子,从而得到融合图像的小波系数;最后利用小波逆变换得到融合图像.采用均方根误差、峰值信噪比、熵、交叉熵和互信息5种准则评价融合算法的性能.实验结果表明,文中方法具有良好的融合特性.     

支持向量机的混合核函数参数优选方法

针对支持向量机中混合核函数参数的选取还没有一套完整的理论支撑,提出基于蚁群算法和循环交叉验证法的参数优选方法。以平均加权误差作为不同参数下支持向量机预测效果的评价指标,采用循环交叉验证法计算平均加权误差。采用蚁群算法来提高混合核函数参数优化效率,减少计算工作量。通过在某型飞机机体研制费用预测中的应用,显示基于最优参数下混合核函数的支持向量机的预测误差最小,表明该参数优选方法能够提高预测精度。     

Phase correlation based redundancy removal in feature weighting band selection for hyperspectral images

Feature weighting based band selection provides a computationally undemanding approach to reduce the number of hyperspectral bands in order to decrease the computational requirements for processing large hyperspectral data sets. In a recent feature weighting based band selection method, a pair‐wise separability criterion and matrix coefficients analysis are used to assign weights to original bands, after which bands identified to be redundant using cross correlation are removed, as it is noted that feature weighting itself does not consider spectral correlation. In the present work, it is proposed to use phase correlation instead of conventional cross correlation to remove redundant bands in the last step of feature weighting based hyperspectral band selection. Support Vector Machine (SVM) based classification of hyperspectral data with a reduced number of bands is used to evaluate the classification accuracy obtained with the proposed approach, and it is shown that feature weighting band selection with the proposed phase correlation based redundant band removal method provides increased classification accuracy compared to feature weighting band selection with conventional cross correlation based redundant band removal.     

An application of a delimitative and combinatorial algorithm to the discrete optimum design of structures

In the present algorithm, the lower bounds of combinations are defined by the constraint functions, and the upper bounds by the objective function step by step in the search procedure, accompanying the fact that a series of infeasible and nonoptimum combinations are eliminated. The advantages of this algorithm are that computational effort is decreased and the effectiveness is increased significantly.