基于SA-PSO的小波神经网络汽轮机故障诊断

针对传统小波神经网络的问题,提出了一种基于模拟退火粒子群算法优化小波神经网络并用于汽轮机故障诊断.先使用模拟退火粒子群算法对小波神经网络的参数进行初步优化,再用小波神经网络进行二次优化训练.实验结果表明,所提出的SA-PSO-WNN算法与WNN、PSO-WNN算法相比,网络的训练速度更快,全局搜索能力更强,网络的泛化能力更好,具有很好的实用价值.     

Legendre神经网络非线性信道均衡

在分析Chebyshev正交多项式神经网络非线性滤波器的基础上，利用Legendre正交多项式快速逼近的优良特性以及判决反馈均衡器的结构特点，提出了两种新型结构的非线性均衡器，并利用NLMS算法，推导出自适应算法．仿真表明，无论通信信道是线性还是非线性，Legendre神经网络自适应均衡器与Chebyshev神经网络均衡器的各项性能均接近，而Legendre神经网络判决反馈自适应均衡器能够更有效地消除码间干扰和非线性干扰，误码性能也得到较好的改善．     

基于SCFNN之PAM非线性信道均衡器成效研究

自组织型模糊类神经网络(SCFNN)可依据一定的法则自我构建神经网络的组织结构,从而适用于当前控制对象;多层神经元是传统的类神经网络,广泛应用于各个领域;倒传递学习法与最陡坡降法相结合,可使以上两种类神经网络进行有效的融合;目前,信道均衡器上的系统架构种类非常多,各种类神经网络应用于信道均衡器也颇为普遍;在研究SCFNN的基础上,将其应用于通道均衡器确实可行,效果良好;比较了SCFNN与MLP在通道均衡器的成效;仿真表明,在相同通道环境下,SCFNN的训练收敛速度、位错误率与系统敏感度优于MLP,完成结构学习后SCFNN的结构也颇为精简。     

Adaptively Combined FIR and Functional Link Artificial Neural Network Equalizer for Nonlinear Communication Channel

This paper proposes a novel computational efficient adaptive nonlinear equalizer based on combination of finite impulse response (FIR) filter and functional link artificial neural network (CFFLANN) to compensate linear and nonlinear distortions in nonlinear communication channel. This convex nonlinear combination results in improving the speed while retaining the lower steady-state error. In addition, since the CFFLANN needs not the hidden layers, which exist in conventional neural-network-based equalizers, it exhibits a simpler structure than the traditional neural networks (NNs) and can require less computational burden during the training mode. Moreover, appropriate adaptation algorithm for the proposed equalizer is derived by the modified least mean square (MLMS). Results obtained from the simulations clearly show that the proposed equalizer using the MLMS algorithm can availably eliminate various intensity linear and nonlinear distortions, and be provided with better anti-jamming performance. Furthermore, comparisons of the mean squared error (MSE), the bit error rate (BER), and the effect of eigenvalue ratio (EVR) of input correlation matrix are presented.     

基于改进粒子群优化算法的新型小波神经网研究

本文提出了改进的粒子群优化算法（Improved Particle Swarm Optimization,IPSO）的新型BP 小波 神经网络,并且对非线性辨识问题进行了仿真实验．实验结果表明,基于改进的粒子群优化算法的BP 小波网 络不仅具有小波分析良好的局部特性以及神经网络的学习、分类能力,而且具有粒子群优化算法全局快速寻 优的特点．与简单的粒子群优化算法相比,该方法在收敛性和稳定性方面都有了较明显的提高,验证了它的 合理性和有效性．     

Pipelined functional link artificial recurrent neural network with the decision feedback structure for nonlinear channel equalization

This paper presents a computationally efficient nonlinear adaptive filter by a pipelined functional link artificial decision feedback recurrent neural network (PFLADFRNN) for the design of a nonlinear channel equalizer. It aims to reduce computational burden and improve nonlinear processing capabilities of the functional link artificial recurrent neural network (FLANN). The proposed equalizer consists of several simple small-scale functional link artificial decision feedback recurrent neural network (FLADFRNN) modules with less computational complexity. Since it is a module nesting architecture comprising a number of modules that are interconnected in a chained form, its performance can be further improved. Moreover, the equalizer with a decision feedback recurrent structure overcomes the unstableness thanks to its nature of infinite impulse response structure. Finally, the performance of the PFLADFRNN modules is evaluated by a modified real-time recurrent learning algorithm via extensive simulations for different linear and nonlinear channel models in digital communication systems. The comparisons of multilayer perceptron, FLANN and reduced decision feedback FLANN equalizers have clearly indicated the convergence rate, bit error rate, steady-state error and computational complexity, respectively, for nonlinear channel equalization.     

Communication channel equalization using wavelet network

Wavelet network (WN) based on wavelet decomposition principle is applied to channel equalization for both linear and non-linear channels. The WN is trained by extended Kalman filter (EKF) based recursive algorithm and is compared with EKF based multi-layered perceptron (MLP) and radial basis function neural network (RBFNN). Exhaustive simulation study reveals the superiority of the WN based equalizer in terms of bit error rate performance, compared to the above equalizer scheme.     

Nonlinear channel equalizer design using directional evolutionary multi-objective optimization

In this paper, a new equalizer learning scheme is introduced based on the algorithm of the directional evolutionary multi-objective optimization (EMOO). Whilst nonlinear channel equalizers such as the radial basis function (RBF) equalizers have been widely studied to combat the linear and nonlinear distortions in the modern communication systems, most of them do not take into account the equalizers’ generalization capabilities. In this paper, equalizers are designed aiming at improving their generalization capabilities. It is proposed that this objective can be achieved by treating the equalizer design problem as a multi-objective optimization (MOO) problem, with each objective based on one of several training sets, followed by deriving equalizers with good capabilities of recovering the signals for all the training sets. Conventional EMOO which is widely applied in the MOO problems suffers from disadvantages such as slow convergence speed. Directional EMOO improves the computational efficiency of the conventional EMOO by explicitly making use of the directional information. The new equalizer learning scheme based on the directional EMOO is applied to the RBF equalizer design. Computer simulation demonstrates that the new scheme can be used to derive RBF equalizers with good generalization capabilities, i.e., good performance on predicting the unseen samples.     

小波神经网络模型的改进方法

为了改善小波神经网络(WNN)在处理复杂非线性问题的性能,针对量子粒子群优化(QPSO)算法易早熟、后期多样性差、搜索精度不高的缺点,提出一种同时引入加权系数、引入Cauchy随机数、改进收缩扩张系数和引入自然选择的改进量子粒子群优化算法,将其代替梯度下降法,训练小波基系数和网络权值,再将优化后的参数组合输入小波神经网络,以实现算法的耦合。通过对3个UCI标准数据集的仿真实验表明,与WNN、PSO-WNN、QPSO-WNN算法相比,改进的量子粒子群小波神经网络(MQPSO-WNN)算法的运行时间减少了11%~43%,而计算相对误差较之降低了8%~57%。因此,改进的量子粒子群小波神经网络模型能够更迅速、更精确地逼近最优值。     

A novel concept of embedding orthogonal basis function expansion block in a neural equalizer structure for digital communication channel

The proposed neural equalizer structure is based on a novel orthogonal basis function (OBF) expansion technique, motivated by genetic evolutionary concept, which utilizes a self-breeding approach to evolve new information to consolidate the final output. Here, the decision at a feedforward neural network (FNN) node termed as expert opinion of a generation undergoes an orthogonal expansion in two dimensions, where one of the outputs possessing the knowledge base for that generation participates in taking the final decision. Hence, a collective judgment based on the expert opinions evolved from decisions of individual generations gives a more rational and heuristic solution compared to a conventional feedforward neural network (CFNN) structure. Propagation of output error backwards and calculation of local gradients at each node become a difficult task as the OBF block is positioned in between the neurons of different layers. In order to circumvent such situation, a new technique has been evolved. The developed equalizer structure using this concept has outperformed the CFNN equalizer with wide margins. Further their bit-error-rate performances are close to that of Bayesian equalizer, which is optimal in the theoretic sense. Application of this proposed technique also reduces the structural and computational complexity of conventional neural equalizers. Hence, this efficient equalizer structures suitable for digital communication channels have the potential for real-time implementation in DSP, FPGA processors also.     

Neural equalization applied to systems with bidimensional digital modulation

A new equalization model for digital communication systems is proposed, based on a multi-layer perceptron (MLP) artificial neural network with a backpropagation algorithm. Unlike earlier techniques, the proposed model, called the bidimensional neural equalizer, is composed of two independent MLP networks that operate in parallel for each dimension of the digital modulation scheme. A heuristic method to combine the errors of the two MLP networks is also proposed, with the aim of reducing the convergence time. Simulations performed for linear and nonlinear channels demonstrated that the new model could improve performance in terms of the bit error rate and the convergence time, compared to existing models.     

Fast Blind Equalization Using Complex-Valued MLP

The blind equalizers based on complex valued feedforward neural networks, for linear and nonlinear communication channels, yield better performance as compared to linear equalizers. The learning algorithms are, generally, based on stochastic gradient descent, as they are simple to implement. However, these algorithms show a slow convergence rate. In the blind equalization problem, the unavailability of the desired output signal and the presence of nonlinear activation functions make the application of recursive least squares algorithm difficult. In this letter, a new scheme using recursive least squares algorithm is proposed for blind equalization. The learning of weights of the output layer is obtained by using a modified version of constant modulus algorithm cost function. For the learning of weights of hidden layer neuron space adaptation approach is used. The proposed scheme results in faster convergence of the equalizer.     

Communication channel equalization using complex-valued minimalradial basis function neural networks

A complex radial basis function neural network is proposed for equalization of quadrature amplitude modulation (QAM) signals in communication channels. The network utilizes a sequential learning algorithm referred to as complex minimal resource allocation network (CMRAN) and is an extension of the MRAN algorithm originally developed for online learning in real-valued radial basis function (RBF) networks. CMRAN has the ability to grow and prune the (complex) RBF network's hidden neurons to ensure a parsimonious network structure. The performance of the CMRAN equalizer for nonlinear channel equalization problems has been evaluated by comparing it with the functional link artificial neural network (FLANN) equalizer of J.C. Patra et al. (1999) and the Gaussian stochastic gradient (SG) RBF equalizer of I. Cha and S. Kassam (1995). The results clearly show that CMRANs performance is superior in terms of symbol error rates and network complexity.     

A hybrid PSO-GD based intelligent method for machine diagnosis

This paper presents an intelligent methodology for diagnosing incipient faults in rotating machinery. In this fault diagnosis system, wavelet neural network techniques are used in combination with a new evolutionary learning algorithm. This new evolutionary learning algorithm is based on a hybrid of the constriction factor approach for particle swarm optimization (PSO) technique and the gradient descent (GD) technique, and is thus called HGDPSO. The HGDPSO is developed in such a way that a constriction factor approach for particle swarm optimization (CFA for PSO) is applied as a based level search, which can give a good direction to the optimal global region, and a local search gradient descent (GD) algorithm is used as a fine tuning to determine the optimal solution at the final. The effectiveness of the HGDPSO based WNN is demonstrated through the classification of the fault signals in rotating machinery. The simulated results show its feasibility and validity.     

Prediction and identification using wavelet-based recurrent fuzzy neural networks

This paper presents a wavelet-based recurrent fuzzy neural network (WRFNN) for prediction and identification of nonlinear dynamic systems. The proposed WRFNN model combines the traditional Takagi-Sugeno-Kang (TSK) fuzzy model and the wavelet neural networks (WNN). This paper adopts the nonorthogonal and compactly supported functions as wavelet neural network bases. Temporal relations embedded in the network are caused by adding some feedback connections representing the memory units into the second layer of the feedforward wavelet-based fuzzy neural networks (WFNN). An online learning algorithm, which consists of structure learning and parameter learning, is also presented. The structure learning depends on the degree measure to obtain the number of fuzzy rules and wavelet functions. Meanwhile, the parameter learning is based on the gradient descent method for adjusting the shape of the membership function and the connection weights of WNN. Finally, computer simulations have demonstrated that the proposed WRFNN model requires fewer adjustable parameters and obtains a smaller rms error than other methods.     

基于QPSO的小波分数间隔盲均衡算法

在分析具有量子行为的粒子群优化(PSO)算法和正交小波变换理论的基础上,提出基于量子粒子群优化(QPSO)的正交小波分数间隔常模盲均衡算法。通过对分数间隔均衡器输入信号进行正交小波变换,降低信号的自相关性。利用QPSO算法全局搜索能力强、收敛速度快和鲁棒性高的特性,对均衡器权向量进行优化。仿真结果表明,该算法能降低稳态误差,加快收敛速度,提高水声信道中信号的无失真传输性能。     

An intelligent biological inspired evolutionary algorithm for the suppression of incubator interference in premature infants ECG

Electromagnetic interference produced by the incubator medical equipments may interrupt or degrade the premature infant’s electrocardiography (ECG) signal. The premature infant’s ECG is usually contaminated by an interference caused by the incubator devices. The interference cancellation system is designed using an adaptive learning ability of artificial neural network Levenberg–Marquardt (LM) algorithm. In this paper the swarm intelligent-LM algorithm is used for the electromagnetic interference cancellation in infant ECG signal. The swarm intelligent algorithm is used for the optimization by selecting the optimized number of neurons in the hidden layer, learning rate and momentum factor of the neural network. Also, this paper presents a comparison of residual mean square error (RMSE) values for neural network trained by LM algorithm, hybrid genetic-LM algorithm and hybrid swarm intelligent-LM algorithm. The LM algorithm is used for the weight updating and reducing the content of electromagnetic interference noise present in the signal. The performance analysis of the proposed noise cancellation approach is compared with gradient based and evolutionary based algorithms. The result analysis shows that the interferences in infant ECG signal is removed successfully using the proposed approach.     

神经网络泛化性能优化算法

基于提高神经网络泛化性能的目标提出了神经网络泛化损失率的概念,解析了与前一周期相比当前网络误差的变化趋势,在此基础上导出了基于泛化损失率的神经网络训练目标函数.利用新的目标函数和基于量子化粒子群算法的神经网络训练方法,得到了一种新的网络泛化性能优化算法.实验结果表明,将该算法与没有引入泛化损失率的算法相比,网络的收敛性能和泛化性能都有明显提高.     

A novel parallel hybrid intelligence optimization algorithm for a function approximation problem

A novel parallel hybrid intelligence optimization algorithm (PHIOA) is proposed based on combining the merits of particle swarm optimization with genetic algorithms. The PHIOA uses the ideas of selection, crossover and mutation from genetic algorithms (GAs) and the update velocity and situation of particle swarm optimization (PSO) under the independence of PSO and GAs. The proposed algorithm divides the individuals into two equation groups according to their fitness values. The subgroup of the top fitness values is evolved by GAs and the other subgroup is evolved by the PSO algorithm. The optimal number is selected as a global optimum at every circulation which shows better results than both PSO and GAs, then improves the overall performance of the algorithm. The PHIOA is used to optimize the structure and parameters of the fuzzy neural network. Finally, the experimental results have demonstrated the superiority of the proposed PHIOA to search the global optimal solution. The PHIOA can improve the error accuracy while speeding up the convergence process, and effectively avoid the premature convergence to compare with the existing methods.     

钢包炉配料PSO-BP-PID 控制研究

针对钢包精炼炉( Ladle Ｒefining Furnace) 又称LF 炉,配料加料过程的惯性、时滞、非线性等控制特性,设计了一种基于微粒群优化算法( Particle Swarm Optimization,PSO) 、误差反向传播( Back Propagation,BP) 神经网络以及比例－ 积分－ 微分( PID) 的复合控制算法PSO-BP-PID,并将该复合算法应用于150 t 钢包精炼炉配料称重控制系统中,实现配料称重过程的智能控制。PSO-BP-PID 算法利用微粒群优化算法的全局寻优特性,优化BP 神经网络的初始权值以提高神经网络的收敛性; 采用经微粒群算法优化后的BP 神经网络在线实时调整PID参数。通过基于PSO 和BP 网络的PID 控制器实时控制钢包精炼沪的配料过程。仿真实验和运行实验结果表明,PSO-BP-PID 算法的控制效果优于单一PID 算法的控制效果。采用PSO-BPPID算法的钢包炉配料系统后,明显提高了配料精度,有效地解决了配料称重过程中速度与精度的矛盾。