file-type

模糊集合与模糊神经网络基础

PPT文件

下载需积分: 50 | 676KB | 更新于2024-07-17 | 189 浏览量 | 33 下载量 举报 2 收藏
download 立即下载
"该资源是关于模糊神经网络的介绍,主要探讨了模糊理论及其在处理模糊概念中的应用。模糊集合允许元素对集合的隶属度在0到1之间变化,通过隶属函数来描述这种不确定性。模糊神经网络结合了模糊逻辑和神经网络的优势,用于处理和学习具有模糊性的复杂系统。" 在模糊理论中,1965年由L.A.Zadeh教授提出的模糊集合概念是关键,它打破了传统集合论中的非黑即白界限,引入了隶属度的概念,使得元素可以部分属于某个集合。例如,对于“老年人”这个集合,一个人的年龄可以有不同程度的“老年”属性,50岁的人可能只有较低的隶属度,而70岁的人则可能有较高的隶属度。隶属函数用来定义这种程度,它是一个从论域到[0,1]区间的映射,0表示完全不隶属,1表示完全隶属。 模糊神经网络是模糊理论与神经网络的结合,它利用模糊逻辑处理不确定性和模糊信息,同时利用神经网络的学习能力来适应和优化模糊规则。在处理如“雨的大小”、“风的强弱”等模糊概念时,模糊神经网络可以通过调整隶属函数和模糊规则,实现对这些模糊属性的有效建模和决策。 在实际应用中,模糊神经网络能够处理那些传统精确方法难以解决的问题,比如人类直观判断的情况。比如,人们可以快速识别“胖子”和“瘦子”,无需精确测量体重,也能明智地躲避繁忙的交通,甚至理解草书文字,这些都是基于人类对模糊概念的理解和处理。在工程研究设计领域,模糊神经网络对于那些需要定量分析模糊数据的问题尤为有用。 举例来说,我们可以定义“年轻”和“年老”两个模糊集合,通过定义不同的隶属函数来描述不同年龄对这两个集合的隶属程度。比如,100岁的个体完全属于“年老”,而50岁的个体可能部分属于“年老”和“年轻”,具体隶属度可以根据实际需求设定。 模糊神经网络通过模糊集合和隶属函数的概念,为理解和处理现实世界中的模糊现象提供了一种有效工具,它可以模拟人类的模糊推理,并在各种复杂系统中实现智能决策和控制。

相关推荐

filetype
It is known that there is no sufficient Matlab program about neuro-fuzzy classifiers. Generally, ANFIS is used as classifier. ANFIS is a function approximator program. But, the usage of ANFIS for classifications is unfavorable. For example, there are three classes, and labeled as 1, 2 and 3. The ANFIS outputs are not integer. For that reason the ANFIS outputs are rounded, and determined the class labels. But, sometimes, ANFIS can give 0 or 4 class labels. These situations are not accepted. As a result ANFIS is not suitable for classification problems. In this study, I prepared different adaptive neuro-fuzzy classifiers. In the all programs, which are given below, I used the k-means algorithm to initialize the fuzzy rules. For that reason, the user should give the number of cluster for each class. Also, Gaussian membership function is only used for fuzzy set descriptions, because of its simple derivative expressions The first of them is scg_nfclass.m. This classifier based on Jang’s neuro-fuzzy classifier [1]. The differences are about the rule weights and parameter optimization. The rule weights are adapted by the number of rule samples. The scaled conjugate gradient (SCG) algorithm is used to determine the optimum values of nonlinear parameters. The SCG is faster than the steepest descent and some second order derivative based methods. Also, it is suitable for large scale problems [2]. The second program is scg_nfclass_speedup.m. This classifier is similar the scg_nfclass. The difference is about parameter optimization. Although it is based on SCG algorithm, it is faster than the traditional SCG. Because, it used least squares estimation method for gradient estimation without using all training samples. The speeding up is seemed for medium and large scale problems [2]. The third program is scg_power_nfclass.m. Linguistic hedges are applied to the fuzzy sets of rules, and are adapted by SCG algorithm. By this way, some distinctive features are emphasized by power values, and some irrelevant features are damped with power values. The power effects in any feature are generally different for different classes. The using of linguistic hedges increase the recognition rates [3]. The last program is scg_power_nfclass_feature.m. In this program, the powers of fuzzy sets are used for feature selection [4]. If linguistic hedge values of classes in any feature are bigger than 0.5 and close to 1, this feature is relevant, otherwise it is irrelevant. The program creates a feature selection and a rejection criterion by using power values of features. References: [1] Sun CT, Jang JSR (1993). A neuro-fuzzy classifier and its applications. Proc. of IEEE Int. Conf. on Fuzzy Systems, San Francisco 1:94–98.Int. Conf. on Fuzzy Systems, San Francisco 1:94–98 [2] B. Cetişli, A. Barkana (2010). Speeding up the scaled conjugate gradient algorithm and its application in neuro-fuzzy classifier training. Soft Computing 14(4):365–378. [3] B. Cetişli (2010). Development of an adaptive neuro-fuzzy classifier using linguistic hedges: Part 1. Expert Systems with Applications, 37(8), pp. 6093-6101. [4] B. Cetişli (2010). The effect of linguistic hedges on feature selection: Part 2. Expert Systems with Applications, 37(8), pp 6102-6108. e-mail:[email protected] [email protected]
bayan2
  • 粉丝: 0
上传资源 快速赚钱