基于混合聚类算法的模糊函数系统辨识方法

针对传统模糊系统存在的结构难以确定和参数辨识复杂的问题,提出了一种基于混合聚类算法的模糊函数系统辨识算法.与一般的模糊函数系统相比,混合聚类算法结合模糊C均值和模糊C回归模型聚类算法的样本距离.在模型预测部分,采用高斯函数计算每个输入变量的隶属度,利用输入变量隶属度的模糊化算子得到输入向量的隶属度.应用于Box-Jenkins煤气炉数据、一个双入单出的非线性系统和Mackey-Glass混沌时间序列数据的试验结果表明,本文算法具有很好的辨识效果,从而验证了本文算法的有效性与实用性.     

基于密度聚类的神经模糊系统建模算法

神经模糊系统经常被用来对非线性系统建模,并能取得很好的效果.以往的模糊系统建模方法存在着输入空间划分个数难以确定和规则冗余的问题,这些问题阻碍了模糊系统的应用.基于动态阈值DENCLUE和相似规则合并的神经模糊系统建模算法DDTSRM(DENCLUE using a dynamic threshold and similar rules merging),首先在DENCLUE算法中使用动态阈值来合并密度吸引子,得到DDT算法.DDTSRM利用DDT算法不依赖初始参数的特点,解决了输入空间划分个数难以确定的问题.因为DDT算法可以得到任意形状和任意密度的聚类结果的特性,所以提高了模糊系统模型的准确性.辨识出模型的初始结构后,DDTSRM通过计算模糊集合之间的相似度来减少规则冗余,使模糊系统模型结构得到优化.最后利用BP算法对系统模型进行训练,进而提高系统的建模精度.以S-Y模糊系统模型为原型,在两输入一输出的非线性函数和Box-Jenkins数据上的仿真实验证明了DDTSRM算法在神经模糊系统建模应用的有效性,能够取得精确的建模效果.     

基于一型模糊规则自主构建二型TSK神经模糊系统方法设计

本文提出了一种使用一型模糊规则生成区间二型TSK(Takagi-Sugeno-Kang)神经模糊系统的新方法.该方法以训练数据集与使用自组织方法由该训练集训练生成的一型模糊系统为驱动,通过新型模糊系统前件类型转换算法与规则参数自适应学习算法的训练,在不高于原一型系统模糊集合总数前提下,自主构建区间二型TSK神经模糊系统.此外,针对两种典型的多输入单输出和多输入多输出系统,在3种不同强度的系统扰动场景下进行了对比仿真实验.实验结果表明,在含有不同扰动状态系统的建模与辨识中本方法较于对比方法具有更加优异的性能.     

基于一型规则自主构建二型TSK神经模糊系统方法设计

本文提出了一种使用一型模糊规则生成区间二型TSK(Takagi-Sugeno-Kang)神经模糊系统的新方法. 该方 法以训练数据集与使用自组织方法由该训练集训练生成的一型模糊系统为驱动,通过新型模糊系统前件类型转换 算法与规则参数自适应学习算法的训练,在不高于原一型系统模糊集合总数前提下,自主构建区间二型TSK神经模 糊系统.此外, 针对两种典型的多输入单输出和多输入多输出系统, 在3种不同强度的系统扰动场景下进行了对比仿 真实验. 实验结果表明, 在含有不同扰动状态系统的建模与辨识中本方法较于对比方法具有更加优异的性能.     

基于动态模糊粒神经网络算法的负荷辨识

针对电力负荷的时变、变结构和非线性等特点,提出一种动态模糊粒神经网络算法.该算法采用粒计算商空间理论和模糊神经网络技术对电力负荷进行建模.将椭圆基函数和模糊ζ-完备性作为在线参数分配机制,避免了初始化选择的随机性.根据模糊规则和输入变量的重要性,对每条规则的输入变量宽度实施在线自适应调整,从而实现了负荷参数和结构同时辨识.实验结果表明了所提出方法的可行性和有效性.     

融合改进蚁狮算法和T-S模糊模型的噪声非线性系统辨识

针对传统的T-S模糊辨识方法难以准确辨识含噪声的非线性系统问题,将噪声信号和系统的其他输入变量一起作为模糊前件的输入,采用具有动态随机搜索和寻优半径连续收缩机制的改进蚁狮算法优化模糊前件的结构参数,使用加权最小二乘法实现模糊后件的参数辨识.数值仿真表明,所提出的辨识方法可以有效抑制噪声的影响,经过改进蚁狮算法优化后的T-S模糊模型辨识效果更好.最后,将所提出方法用于直拉硅单晶生长热模型的辨识,实验结果表明该方法优于传统的辨识方法.     

一种能处理定性参数输入的推广模糊神经网络软测量建模方法

针对生产过程中存在多种类属型数据和混合型数据,而大多数软测量方法只能处理数值型数据的问题,提出了一种基于粗糙集方法的推广模糊神经网络软测量建模方法,该方法既可以接受定量参数输入,也可以接受定性参数输入.首先建立模糊-清晰混合规则的定义,对具有混合类型属性的样本集进行离散化处理后,利用粗糙集的约简算法进行规则提取,获得最小决策集.由得到的混合决策规则构建推广模糊神经网络,使用样本集训练网络参数.最后将该方法应用于蒸发器的污垢热阻值估计,取得了良好的效果.     

规则可生长与修剪的非线性系统T-S模糊模型辨识

通常离线提取 T-S 模糊模型的规则后, 规则数无法在模型使用中进行调整, 而这成为表达非线性系统复杂性的一个瓶颈. 针对这一问题, 本文引入一种神经网络的生长和修剪方法, 从实时数据中提取 T-S 模型的规则, 并定义其对应局部模型对输出的影响, 以此作为在线调整规则数的依据, 从而更准确地表达了非线性系统的复杂性和运行中的变化. 再加上基于竞争性 EKF(Extended Kalman filter) 的模型参数在线学习, T-S 模型的建模精度也得到了保证. 整个算法完全实现了 T-S 模糊模型的在线辨识, 使模型的结构和参数具有很好的自适应能力. 对 CSTR(Continuously stirred tank reactor) 系统的辨识, 表明了该算法在处理非线性系统辨识问题上的优越性能.     

基于遗传算法的模糊树建模方法

1　引言近年来模糊逻辑理论在非线性系统辨识领域中得到了广泛的应用 .模糊逻辑建模方法的主要内容可分为两个层次 ,一是模型结构的辨识 ,另一则是模型参数的估计 .模糊模型的结构辨识问题是指如何划分输入空间 .模糊树模型 (FT模型 )是一种利用二叉树结构描述输入空间模糊划分     

基于神经网络的自适应模糊控制器

本文提出了一种基于神经网络的自适应模糊控制器，控制器为５层前向结构，其输入和输出均为数值量。根据给定的训练数据，通过学习算法，能够实现前件参数和后件参数的辨识，提取控制规则，最后通过仿真实验证明了这种方法的有效性。     

Hierarchical wavelet packet fuzzy inference system for pattern classification and system identification

This study presents a hierarchical Takagi–Sugeno–Kang type fuzzy system called hierarchical wavelet packet fuzzy inference system. In the proposed method, wavelet packet transform is applied on the input data to produce approximation and detail sub-bands of the input data and the output is used as the input vector of the proposed network. This network uses a hierarchical structure same as wavelet packet decomposition tree, in which adaptive network-based fuzzy inference system is used as sub-model. Also, gradient descent algorithm is chosen for training the parameters of antecedent and conclusion parts of the sub-models. In order to evaluate the capability of the proposed method, its applications in pattern classification, system identification and time-series prediction have been studied. The results show that the proposed method performs better than the other conventional models.     

A structure identification method of submodels for hierarchical fuzzy modeling using the multiple objective genetic algorithm

Fuzzy models describe nonlinear input‐output relationships with linguistic fuzzy rules. A hierarchical fuzzy modeling is promising for identification of fuzzy models of target systems that have many input variables. In the identification, (1) determination of a hierarchical structure of submodels, (2) selection of input variables of each submodel, (3) division of input and output space, (4) tuning of membership functions, and (5) determination of fuzzy inference method are carried out. This article presents a hierarchical fuzzy modeling method with an uneven division method of input space of each submodel. For selecting input variables of submodels, the multiple objective genetic algorithm (MOGA) is utilized. MOGA finds multiple models with different input variables and different numbers of fuzzy rules as compromising solutions. A human designer can choose desirable ones from these candidates. The proposed method is applied to acquisition of fuzzy rules from cyclists' pedaling data. In spite of a small number of data, the obtained model was able to give detailed suggestions to each cyclist. © 2002 Wiley Periodicals, Inc.     

基于过程输入输出变化关系的模糊建模方法

针对难以建立精确数学模型的复杂过程,提出一种基于过程输入输出数据变化关系的模糊建模方法。首先按过程输出随输入变量变化的程度对输入变量论域进行划分,在此基础上确定模糊模型的规则总数和前件参数;然后根据所建模糊模型可表示为一个前馈模糊神经网络,利用BP学习算法求得过程模糊模型的后件参数。仿真例子验证了模糊建模方法的有效性,同时表明所建模糊规则模型较好的泛化能力。     

一种模糊逻辑系统的快速学习算法

本文提出了一种模糊逻辑系统的快速学习算法．算法要求预先确定各输入变量上模 糊集合的数目及分布;模糊规则前件可以是任意形状的模糊集合,后件则必须采用单值模糊 集合;模糊推理采用乘积推理;解模糊方法采用Tsukamoto方法．算法由输入－输出数据对 提取模糊规则．模糊规则的后件采用最小二乘方法一次计算得出．本算法对目标对象的逼近 精度取决于输入参数上模糊集合的数目,数目越多,精度越高．算法所需计算量小．     

基于ANFIS和减法聚类的遥感红外目标分选

针对自适应神经模糊推理系（ANFIS）的结构特点，本文应用多个ANFIS组合的网络来解决多目标分选问题。为了给ANFIS赋予一个合适的初始状态，减法聚类被用于预处理输入特征数据，实现了网络结构和初始参数的优化。基于ANFIS的红外航母和大型舰船目标分选仿真实验证明，其学习速度快、目标分选准确。     

模糊规则的学习及其在非线性系统建模中的应用

探讨用神经网络的学习算法及模糊推理方法为非线性系统建模的问题.给出了学 习模糊规则的新算法.这个算法首先用竞争学习为训练样本的输入空间进行聚类,然后为其 确定区域划分边界,并按样本输入区域学习模糊规则.文中对于模糊规则提出了相应的模糊 推理算法.并用算例验证了本文算法的有效性.     

A new approach to fuzzy modeling of nonlinear dynamic systems with noise: relevance vector learning mechanism

This paper presents a new fuzzy inference system for modeling of nonlinear dynamic systems based on input and output data with measurement noise. The proposed fuzzy system has a number of fuzzy rules and parameter values of membership functions which are automatically generated using the extended relevance vector machine (RVM). The RVM has a probabilistic Bayesian learning framework and has good generalization capability. The RVM consists of the sum of product of weight and kernel function which projects input space into high dimensional feature space. The structure of proposed fuzzy system is same as that of the Takagi-Sugeno fuzzy model. However, in the proposed method, the number of fuzzy rules can be reduced under the process of optimizing a marginal likelihood by adjusting parameter values of kernel functions using the gradient ascent method. After a fuzzy system is determined, coefficients in consequent part are found by the least square method. Examples illustrate effectiveness of the proposed new fuzzy inference system.     

Using Bayesian networks with rule extraction to infer the risk of weed infestation in a corn-crop

This paper describes the modeling of a weed infestation risk inference system that implements a collaborative inference scheme based on rules extracted from two Bayesian network classifiers. The first Bayesian classifier infers a categorical variable value for the weed–crop competitiveness using as input categorical variables for the total density of weeds and corresponding proportions of narrow and broad-leaved weeds. The inferred categorical variable values for the weed–crop competitiveness along with three other categorical variables extracted from estimated maps for the weed seed production and weed coverage are then used as input for a second Bayesian network classifier to infer categorical variables values for the risk of infestation. Weed biomass and yield loss data samples are used to learn the probability relationship among the nodes of the first and second Bayesian classifiers in a supervised fashion, respectively. For comparison purposes, two types of Bayesian network structures are considered, namely an expert-based Bayesian classifier and a naïve Bayes classifier. The inference system focused on the knowledge interpretation by translating a Bayesian classifier into a set of classification rules. The results obtained for the risk inference in a corn-crop field are presented and discussed.     

Gaussian kernel-based fuzzy inference systems for high dimensional regression

We propose a novel architecture for a higher order fuzzy inference system (FIS) and develop a learning algorithm to build the FIS. The consequent part of the proposed FIS is expressed as a nonlinear combination of the input variables, which can be obtained by introducing an implicit mapping from the input space to a high dimensional feature space. The proposed learning algorithm consists of two phases. In the first phase, the antecedent fuzzy sets are estimated by the kernel-based fuzzy c-means clustering. In the second phase, the consequent parameters are identified by support vector machine whose kernel function is constructed by fuzzy membership functions and the Gaussian kernel. The performance of the proposed model is verified through several numerical examples generally used in fuzzy modeling. Comparative analysis shows that, compared with the zero-order fuzzy model, first-order fuzzy model, and polynomial fuzzy model, the proposed model exhibits higher accuracy, better generalization performance, and satisfactory robustness.