Gravitational search algorithm based data scheduling for peer to peer video on demand system

Multimedia Tools and Applications - In peer to peer (P2P) video streaming systems, peers in network assist to forward the data to other peers without the interference of central servers. Video on...     

平面选址问题的引力搜索算法求解

为求解平面选址问题,给出了一种基于引力搜索算法的求解方法。算法利用万有引力定律进行全局搜索,采用一种邻域搜索方法进行局部搜索,实现算法全局优化和局部优化的平衡。通过大量实验和与现有求解方法的比较,结果验证了算法的可行性和有效性。     

Nonlinear system identification and control of chemical processes using fast orthogonal search

The use of the fast orthogonal search (FOS) method is presented for model estimation and control of nonlinear chemical processes. FOS provides a nonlinear approximation used in an inner-loop that allows for simpler linear control methods to be used as an outer-loop controller. It is a straightforward, simple-to-use method for linearization of systems based on orthogonal system identification. The control concept is derived from the method of inverse dynamic control (IDC). The novel combination of this with the FOS method of system identification results in a very efficient and effective method of control. The method is demonstrated and tested on two nonlinear chemical process control simulations and the results are shown to compare very favourably to published results on the same problems.     

Nonlinear system identification using wavelet networks

A novel identification scheme using wavelet networks is presented for nonlinear dynamical systems. Based on fixed wavelet networks, parameter adaptation laws are developed using a Lyapunov synthesis approach. This guarantees the stability of the overall identification scheme and the convergence of both the parameters and the state errors, even in the presence of modelling errors. Using the decomposition and reconstruction techniques of multiresolution decompositions, variable wavelet networks are introduced to achieve a desired estimation accuracy and a suitable sized network, and to adapt to variations of the characteristics and operating points in nonlinear systems. B-spline wavelets are used to form the wavelet networks and the identification scheme is illustrated using a simulated example.     

Harmony search algorithm for infinite impulse response system identification

In this paper, optimal sets of filter coefficients are searched by a meta-heuristic optimization technique called Harmony Search (HS) algorithm for infinite impulse response (IIR) system identification problem. For different optimization problems, HS algorithm undergoes three basic rules; namely Random Selection (RS), Harmony Memory Consideration (HMC), and Pitch Adjustment (PA) rules, which are inspired from the process that the musicians use to improvise a perfect state of harmony with the consummate skill of blending notes in tune. With the help of the properly selected control parameters, a perfect balance is achieved in exploration and exploitation in searching phases. The detailed analysis of simulation results emphasizes the strength of HS algorithm to find the near-global optimal solution, quality of convergence profile and the speed of convergence while tested against standard benchmark examples for same and reduced order models.     

IIR model identification using a modified inclined planes system optimization algorithm

Inclined planes system optimization (IPO) is a new optimization algorithm inspired by the sliding motion dynamic along a frictionless inclined surface. In this paper, with the aim of create a powerful trade-off between the concepts of exploitation and exploration, and rectify the complexity of their structural parameters in the standard IPO, a modified version of IPO (called MIPO) is introduced as an efficient optimization algorithm for digital infinite-impulse-response (IIR) filters model identification. The IIR model identification is a complex and practical challenging problem due to multimodal error surface entanglement that many researches have been reported for it. In this work, MIPO utilizes an appropriate mechanism based on the executive steps of algorithm with the constant damp factors. To do this, unknown filter parameters are considered as a vector to be optimized. In implementation, at first, to demonstrate the effectiveness of the proposed method, 10 well-known benchmark functions have been considered for evaluating and testing. In addition, statistical analysis on the powerfulness, efficiency and applicability of the MIPO algorithm are presented. Obtained results in compared to some other popular methods, confirm the efficiency of the MIPO algorithm that makes the best optimal solutions and has a better performance and acceptable solutions.     

Gravitational search algorithm: a comprehensive analysis of recent variants

Gravitational search algorithm is a nature-inspired algorithm based on the mathematical modelling of the Newton’s law of gravity and motion. In a decade, researchers have presented many variants of gravitational search algorithm by modifying its parameters to efficiently solve complex optimization problems. This paper conducts a comparative analysis among ten variants of gravitational search algorithm which modify three parameters, namely Kbest, velocity, and position. Experiments are conducted on two sets of benchmark categories, namely standard functions and CEC2015 functions, including problems belonging to different categories such as unimodal, multimodal, and unconstrained optimization functions. The performance comparison is evaluated and statistically validated in terms of mean fitness value and convergence graph. In experiments, IGSA has achieved better precision with balanced trade-off between exploration and exploitation. Moreover, triple negative breast cancer dataset has been considered to analysis the performance of GSA variants for the nuclei segmentation. The variants performance has been analysed in terms of both qualitative and quantitive with aggregated Jaccard index as performance measure. Experiments affirm that IGSA-based method has outperformed other methods.

     

Nonlinear system identification using optimized dynamic neural network

In this paper, both off-line architecture optimization and on-line adaptation have been developed for a dynamic neural network (DNN) in nonlinear system identification. In the off-line architecture optimization, a new effective encoding scheme—Direct Matrix Mapping Encoding (DMME) method is proposed to represent the structure of neural network by establishing connection matrices. A series of GA operations are applied to the connection matrices to find the optimal number of neurons on each hidden layer and interconnection between two neighboring layers of DNN. The hybrid training is adopted to evolve the architecture, and to tune the weights and input delays of DNN by combining GA with the modified adaptation laws. The modified adaptation laws are subsequently used to tune the input time delays, weights and linear parameters in the optimized DNN-based model in on-line nonlinear system identification. The effectiveness of the architecture optimization and adaptation is extensively tested by means of two nonlinear system identification examples.     

Nonlinear thermal system identification using fractional Volterra series

Linear fractional differentiation models have already proven their efficacy in modeling thermal diffusive phenomena for small temperature variations involving constant thermal parameters such as thermal diffusivity and thermal conductivity. However, for large temperature variations, encountered in plasma torch or in machining in severe conditions, the thermal parameters are no longer constant, but vary along with the temperature. In such a context, thermal diffusive phenomena can no longer be modeled by linear fractional models. In this paper, a new class of nonlinear fractional models based on the Volterra series is proposed for modeling such nonlinear diffusive phenomena. More specifically, Volterra series are extended to fractional derivatives, and fractional orthogonal generating functions are used as Volterra kernels. The linear coefficients are estimated along with nonlinear fractional parameters of the Volterra kernels by nonlinear programming techniques. The fractional Volterra series are first used to identify thermal diffusion in an iron sample with data generated using the finite element method and temperature variations up to 700 K. For that purpose, the thermal properties of the iron sample have been characterized. Then, the fractional Volterra series are used to identify the thermal diffusion with experimental data obtained by injecting a heat flux generated by a 200 W laser beam in the iron sample with temperature variations of 150 K. It is shown that the identified model is always more accurate than the finite element model because it allows, in a single experiment, to take into account system uncertainties.     

基于广义超曲面树搜索的分类算法

为了深入研究假日旅游者的类别信息,分析了在低维样本空间解决非线性划分问题的可行性,从理论上给出了在样本空间内利用广义超曲面对样本进行分类的方法,在此基础上提出了一个基于广义超曲面树搜索的分类算法.采用广义超曲面树搜索分类的分类方法,对非线性数据进行分类是可行的.测试结果表明广义超曲面树搜索分类法的泛化能力较好,并且可以把此算法推广到更高维数据.     

基于禁忌搜索的蝙蝠算法

为了克服蝙蝠算法(BA)易陷入局部最优,收敛速度过快等缺点,以基本蝙蝠算法为基础,提出了基于禁忌搜索的蝙蝠算法(TSBA)。TSBA算法将蝙蝠算法和禁忌搜索算法相结合,采用禁忌表以及渴望水平函数的策略,使算法具有更强的全局寻优能力,有效地避免了早熟现象。为了验证该算法的有效性,采用0-1背包问题作为测试内容。实验结果表明,基于禁忌搜索的TSBA蝙蝠算法比基本的蝙蝠算法具有更强的寻优能力和搜索速度。     

布谷鸟搜索算法优化BP神经网络的网络流量预测

为了提高预测精度,提出一种布谷鸟搜索算法优化BP神经网络的网络流量预测模型(Cuckoo Search BP neural network Flow Prediction,CS-BPNN)。根据混沌理论建立网络流量学习样本,采用BP神经网络对学习样本进行训练,将模型参数当一个鸟巢,通过模拟布谷鸟寻窝产卵的行为找到最优模型参数,最后采用网络流量数据进行仿真实验,测试模型性能。仿真实验表明:所提出模型较好的解决了BP神经参数优化问题,能够获得更加理想的网络流量预测结果。     

使用搜索结果缓存的混合搜索算法

针对无结构化对等网络中资源搜索效率低、网络带宽消耗高的问题,结合动态搜索算法和缓存技术提出一种使用搜索结果缓存的混合搜索算法(HSUC).该算法按照动态搜索算法进行资源搜索,如果搜索成功,返回资源地址信息,反之,返回搜索失败信息,节点将返回的搜索结果写入缓存作为参考,当其它节点发起相同主题的搜索时,参考该信息进行,不再搜遍整个网络.仿真实验结果表明,该算法改进了资源搜索的盲目性,降低了带宽消耗,提高了搜索成功率.     

Nonlinear system identification using two-dimensional wavelet-based state-dependent parameter models

This article presents a nonlinear system identification approach that uses a two-dimensional (2-D) wavelet-based state-dependent parameter (SDP) model. In this method, differing from our previous approach, the SDP is a function with respect to two different state variables, which is realised by the use of a 2-D wavelet series expansion. Here, an optimised model structure selection is accomplished using a PRESS-based procedure in conjunction with orthogonal decomposition (OD) to avoid any ill-conditioning problems associated with the parameter estimation. Two simulation examples are provided to demonstrate the merits of the proposed approach.     

Nonlinear system identification using BBO-based multilayer perceptron network method

Microsystem Technologies - Recently, nonlinear system identification has received increasingly more attention due to its promising applications in engineering fields. It has become a challenging...     

Nonlinear system identification using a Gabor/Hopfield network

This paper presents a method of nonlinear system identification using a new Gabor/Hopfield network. The network can identify nonlinear discrete-time models that are affine linear in the control. The system need not be asymptotically stable but must be bounded-input-bounded-output (BIBO) stable for the identification results to be valid in a large input-output range. The network is a considerable improvement over earlier work using Gabor basis functions (GBF's) with a back-propagation neural network. Properties of the Gabor model and guidelines for achieving a global error minimum are derived. The new network and its use in system identification are investigated through computer simulation. Practical problems such as local minima, the effects of input and initial conditions, the model sensitivity to noise, the sensitivity of the mean square error (MSE) to the number of basis functions and the order of approximation, and the choice of forcing function for training data generation are considered.     

遗传算法在模糊模型参数辨识中的应用

介绍了T-S模糊模型的建模过程,在现有T-S模糊模型参数辨识方法的基础上,提出了一种先应用最小二乘法对结论参数进行粗略辨识,以确定参数的大致范围之后,再应用遗传算法对前提参数和结论参数同时优化的参数辨识方法,通过MATLAB对本算法进行了仿真,并对非线性函数进行了逼近实验,所取得的结果令人满意。     

基于MapX最短路径搜索算法研究

在深入分析现有最短路径搜索算法和MapX空间特性的基础上,提出了一种基于MapX的局部最短路径搜索算法.该算法依据最短路径沿起点、终点连线方向可能性最大的特征,在小矩形范围内搜索,避免了因道路振荡而产生结果失真的问题,减少了搜索的节点数目,降低了搜索规模.实验结果表明,该算法搜索速度快,道路网络结构越复杂,其运行效率越高,具有很强的实用性.     

基于双栈技术的全路径搜索算法

认真分析了访问图的过程中已被访问结点、未被访问结点以及环路构成成因,设计出全路径搜索算法.算法采用了邻接表作为数据结构,存储图的基本信息,利用双栈技术为辅助的广度优先搜索算法搜索图中任意两点问的全路径.给出全路径搜索算法的特性分析,在最坏的情况下,算法的时间复杂度为D(2*e*n+2*e*b4),并用江苏省高速公路路网信息数据进行验证,得出正确的结果.