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1.
基于梯度的并行协作模块化神经网络体系结构   总被引:2,自引:0,他引:2  
凌卫新  郑启伦  陈琼 《计算机学报》2004,27(9):1256-1263
该文提出了一种基于梯度的并行协作模块化神经网络的体系结构(GPCMNN).它通过分解模块,根据梯度方法对学习样本空间自动分解,由子空间识别模块和子任务模块实现各子样本空间的识别和学习,集成模块将子样本空间结果集成得系统的输出,实现了复杂任务的自动分解、判定和模块化训练策略.实验表明,该文提出的GPCMNN体系结构是可行的、有效的;与非模块化神经网络技术相比,提高了训练速度,改善了网络性能.它具有高效并行的运行效率、便于硬件实现等特点,同时又保持了PCMNN算法的优点,改进了它的不足.  相似文献   

2.
主要针对大训练集和类别非对称训练集等复杂分类问题提出一种基于新的任务分解技术的矩阵模块神经网络分类系统,它将一个复杂分类任务分解为多个简单的子任务来解决,每个子任务只是在两个子空间内进行,且由一个具有简单结构的神经网络模块来完成;所有网络模块将组成一个神经网络矩阵,最终将该神经网络矩阵的输出矩阵集成得到最终分类结果.本文通过理论分析和模拟实验证明,该矩阵模块神经网络能节省神经网络的学习时间,提高泛化能力和分类精度.  相似文献   

3.
Fuzzy Neural Network Models for Classification   总被引:2,自引:0,他引:2  
In this paper, we combine neural networks with fuzzy logic techniques. We propose a fuzzy-neural network model for pattern recognition. The model consists of three layers. The first layer is an input layer. The second layer maps input features to the corresponding fuzzy membership values, and the third layer implements the inference engine. The learning process consists of two phases. During the first phase weights between the last two layers are updated using the gradient descent procedure, and during the second phase membership functions are updated or tuned. As an illustration the model is used to classify samples from a multispectral satellite image, a data set representing fruits, and Iris data set.  相似文献   

4.
分析了模块化神经网络MATLAB仿真系统的设计和实现。该仿真系统充分运用MATLAB对数值计算、图形处理的强大功能,采用可扩展的图形用户界面,开发了一套适合模块化神经网络试验和研究平台。介绍了模块化神经网络(MNN)的子网动态集成方法,并提出了一种基于“一专多能”思想的集成训练方法。该仿真系统将算法、数据、仿真演示有机集成,为后期的设计开发提供了有力的支持。  相似文献   

5.
Bayesian Network Classifiers   总被引:154,自引:0,他引:154  
Friedman  Nir  Geiger  Dan  Goldszmidt  Moises 《Machine Learning》1997,29(2-3):131-163
Recent work in supervised learning has shown that a surprisingly simple Bayesian classifier with strong assumptions of independence among features, called naive Bayes, is competitive with state-of-the-art classifiers such as C4.5. This fact raises the question of whether a classifier with less restrictive assumptions can perform even better. In this paper we evaluate approaches for inducing classifiers from data, based on the theory of learning Bayesian networks. These networks are factored representations of probability distributions that generalize the naive Bayesian classifier and explicitly represent statements about independence. Among these approaches we single out a method we call Tree Augmented Naive Bayes (TAN), which outperforms naive Bayes, yet at the same time maintains the computational simplicity (no search involved) and robustness that characterize naive Bayes. We experimentally tested these approaches, using problems from the University of California at Irvine repository, and compared them to C4.5, naive Bayes, and wrapper methods for feature selection.  相似文献   

6.
文章提出了一种应用于T细胞表位预测的模块化神经网络,这种神经网络先用一个过滤模块将不可结合的蛋白质序列过滤掉,然后将可结合的蛋白质输入到各个分类模块中进行训练学习,最后根据三个分类模块的结果进行最大值判定输出最后结果。实验结果证明,用这种模块化神经网络结构对T细胞表位进行预测比单个BP神经网络具有更高的准确率和数据的自我组织及学习能力。  相似文献   

7.
This paper presents a software tool suitable for dynamic system modelling. The models generated by this tool are modular neural networks, see [1]. Each module behaves like a functional block and is connected to the other modules like in classical block diagrams. This tool allows the inclusion of a priori knowledge and, furthermore, to extract physical information from the models, once the system has learned. The modelling tool is capable of automatic model generation, parameter estimation and model validation.  相似文献   

8.
Several methods (e.g., Bagging, Boosting) of constructing and combining an ensemble of classifiers have recently been shown capable of improving accuracy of a class of commonly used classifiers (e.g., decision trees, neural networks). The accuracy gain achieved, however, is at the expense of a higher requirement for storage and computation. This storage and computation overhead can decrease the utility of these methods when applied to real-world situations. In this Letter, we propose a learning approach which allows a single neural network to approximate a given ensemble of classifiers. Experiments on a large number of real-world data sets show that this approach can substantially save storage and computation while still maintaining accuracy similar to that of the entire ensemble.  相似文献   

9.
基于粗糙集的并行协作模块化神经网络模式分类器   总被引:1,自引:1,他引:0  
该文提出了基于粗糙集的K类模式分类器的体系结构(RSPCMNNC),基于粗糙集理论提出了三个预处理算法,简化了分类器的结构,降低了学习难度,有效地避免产生过多的子网。样本空间基于最大均衡的策略来划分,保证BP算法在学习过程中的有效性。实验结果表明,该文提出的RSPCMNNC分类器显示出更高的识别率,对于实际应用中多特征模式的识别问题,具有很大的实用价值。  相似文献   

10.
11.
A new cooperative modular neural network (CMNN) architecture for classification is introduced. The main idea is to decrease partial over- and under-learning by dealing with different levels of overlap in separate modules. Motivated by some basic biological modular-networks’ concepts, CMNN proposes a new cooperation scheme to integrate the information available at its modules. Cooperative modules utilize some voting techniques to come up with a collective decision. Moreover, the specialization concept is proposed as a solution for high overlap regions in the input space. A number of experiments which assess CMNN’s capabilities are outlined. The experiments compare it to several non-modular and modular state-of-the-art alternatives using several benchmark problems. The proposed modularization scheme proves to be an effective way to deal with the complexities of real classification problems.  相似文献   

12.
针对传统神经网络用于复杂过程系统的控制时难于收敛的问题,文章提出了基于混合建模的模块化的神经网络模型。采取运行机理建模和神经网络建模相结合的方式,把输入样本空间进行划分,实现基于混合专家网络的建模。试验结果表明,对大型燃煤锅炉供热系统,文章提出的方法可以较好地提高供热系统的稳定性和供热质量。  相似文献   

13.
A novel modular neural network architecture and its application to the field of numerical cognition simulation are presented. Previous modular connectionist systems are typically constrained at one of two levels: at the representational level, in that the connectivity of the modules is hard-wired by the modeller; or at a local architectural level, in that the modeller explicitly allocates each module to a specific subtask. Our approach aims to minimise the constraints, thus reducing the bias possibly introduced by the modeller. The efficacy of this approach is demonstrated through the successful simulation of the development of two quantification abilities, subitising and counting, amongst children. It is concluded that such a minimally constrained modular system may contribute to both the capturing of learnt behaviour, and the allocation of modules to subtasks according to the nature of the task.  相似文献   

14.
A Neural Network with Evolutionary Neurons   总被引:1,自引:0,他引:1  
A neural network, combining evolution and learning is introduced. The novel feature of the proposed network is the evolutionary character of its neurons. The argument of the transfer function performed by the neurons in the network is neither a linear nor polynomial function of the inputs to the neuron, but an unknown general function P(·). The adequate functional form P(·) for each neuron, is achieved during the learning period by means of genetic programming. The proposed neural network is applied to the problem domain of time series prediction of the Mackey-Glass delay differential equation. Simulation results indicate that the new neural network is effective.  相似文献   

15.
如何决定人工神经网络的适当规模,以往都是通过试探法实现,不但费时,而且无规律可循。文中基于神经网络的基本学习算法,构筑动态网络结构,使之更符合抽取的新的输入、输出特性。讨论了构筑动态神经网络的一种途径。学习是从最简单的网络(无隐含单元)开始,新的单元一步一步补充,直到网络给出一个满意的模拟值。  相似文献   

16.
Neural and Wavelet Network Models for Financial Distress Classification   总被引:1,自引:0,他引:1  
This work analyzes the use of linear discriminant models, multi-layer perceptron neural networks and wavelet networks for corporate financial distress prediction. Although simple and easy to interpret, linear models require statistical assumptions that may be unrealistic. Neural networks are able to discriminate patterns that are not linearly separable, but the large number of parameters involved in a neural model often causes generalization problems. Wavelet networks are classification models that implement nonlinear discriminant surfaces as the superposition of dilated and translated versions of a single “mother wavelet” function. In this paper, an algorithm is proposed to select dilation and translation parameters that yield a wavelet network classifier with good parsimony characteristics. The models are compared in a case study involving failed and continuing British firms in the period 1997–2000. Problems associated with over-parameterized neural networks are illustrated and the Optimal Brain Damage pruning technique is employed to obtain a parsimonious neural model. The results, supported by a re-sampling study, show that both neural and wavelet networks may be a valid alternative to classical linear discriminant models.  相似文献   

17.
神经网络集成   总被引:175,自引:2,他引:175  
神经网络集成通过训练多个神经网络并将成结论进行合成,可以显著地提高学习系统的泛化能力。它不仅有助于科学家对机器学习和神经的深入研究,还有助于普通工程技术人员利用神经网络技术来解决真实世界中的问题。因此,它被视为一种广阔应用前景的工程化神经计算技术,已经成为机器学习和神经计算领域的研究热点。该文从实现方法、理论分析和应用成果等三个方面综述了神经网络集成的国际研究现状,并对该领域值得进一步研究的一些问题进行了讨论。  相似文献   

18.
提出一类基于多种正交基函数的模块化过程神经元网络模型,它融入了多时变输入的空间聚合和作用域限制的时间累积,并采用多种正交基函数在较小网络规模的条件下保证系统各种输入输出的精度,应用混合隐含层综合考虑了系统多类型输入对系统的作用,并应用模块化级联的方式在一定程度上减小了网络的总体容量,从而提高了整个网络的学习速度。应用实例的训练及仿真结果证明了该模型的可行性和有效性。  相似文献   

19.
互联网的普及和电子商务的飞速发展,网络广告成为一种新的经营方式。然而网络广告形式多样,目前现有的广告投放系统缺乏针对性,使得网络广告精确度不高,不能达到预期的目的。因此,分析用户行为进行精准广告投放成为一种必要。该文采用神经网络技术,对用户行为特征库提炼用户最重要的行为和最关注的内容点,从而对用户进行智能分类,以此作为向用户推荐广告的依据,达到精准投放的目的。  相似文献   

20.
郭新宇 《测控技术》2007,26(8):4-5,11
研究了概率神经网络模型,并应用于故障诊断.对基于概率统计思想和Bayes分类规则的概率神经网络模型、网络结构、算法及其特点进行了分析,并提出一种优化估计平滑因子的方法.概率神经网络可很好地诊断自行火炮发动机运行中油路和气路的故障,在模式识别和故障诊断领域中可取得良好的应用效果.  相似文献   

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