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软测量建模中建模数据的准确与否直接影响到模型的精度,因此通过对建模数据进行过失误差检测可以确保建模数据的质量.文中提出了一种基于聚类分析的过失误差检测方法,该方法脱离了传统检测方法依赖于机理模型的束缚,更好地适应软测量的特点.针对软测量建模过程中建模数据过失误差检测的特性提出了一种新的聚类方法,这种新方法依据各数据点到数据中心的欧氏距离进行聚类,可以有效地将过失误差从数据集中剔除.实验表明这种基于聚类分析的过失误差检测方法具有很好的效果. 相似文献
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针对炼油工业过程存在的多变量、非线性和数据动态性问题,提出一种自回归移动平均模型与径向基函数-加权偏最小二乘相结合的非线性动态建模方法。首先建立基于径向基函数-加权偏最小二乘方法的软测量模型,然后利用自回归移动平均模型对数据进行时序分析校正,将动态误差信息加入到模型中去,实现模型的动态装换。将该方法应用到加氢裂化航煤干点的软测量建模中,从而获得比径向基函数-加权偏最小二乘算法更高的预测精度。 相似文献
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研究了机器人操作环境的动力学模型,提出了一种基于径向基函数(RBF)神经网络的机器人系统中环境非线性动力学模型新的建立方法,阐述了其建模机理和算法.结果表明,采用RBF神经网络对机器人系统中的操作环境建模比用BP神经网络有更高的精度,其网络训练速度也大大快于BP神经网络. 相似文献
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针对复杂非线性结构动力学系统提出了一种基于有限元与神经网络相结合的杂交建模方法。依据该方法,首先将系统中的线性结构部分采用有限元建模,非线性或难以机理建模的结构部件采用神经网络描述。其次,再通过力和位移边界联接条件将有限元模型部分和神经网络模型部分结合从而得到整个系统的杂交模型,且杂交模型的物理结构明确,精度较高,网络规模较小。在一非线性隔振系统的杂交建模算例仿真中,用所建杂交模型对正弦及宽带随机激励进行了预测检验分析,结果良好,该杂交建模方法为主体结构为线弹性结构而又包含有强非线性器件的非线性动力学系统提供了一种有效的建模途径。 相似文献
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医院月门诊量是一个具有复杂的非线性组合特征的季节性时间序列。传统的时间序列趋势分析是通过季节调整建立预测模型,效果不理想。文章提出一种利用季节性神经网络预测模型对医院门诊量进行非线性曲线拟合分析并预测。论述了该模型的设计思想和实现算法。通过仿真实验表明,该模型的非线性曲线拟合精度和预测精度明显高于ARIMA季节乘积模型,可较好地反映系统的动态性和门诊量的季节时序关联性,为季节性时间序列预测提供了一种新的途径。 相似文献
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针对现有的固体氧化物燃料电池(SOFC)模型过于复杂的弊端,提出了一种基于最小二乘支持向量机(LS-SVM)的建模方法,用具有径向基函数(RBF)核函数的LS-SVM建立了SOFC电堆的非线性模型.应用仿真对建模的有效性和精度进行了检验,并与径向基函数神经网络(RBFNN)模型的辨识效果进行了比较.仿真结果证明,与RBFNN模型相比,LS-SVM模型具有较高的预测精度,这表明用LS-SVM对SOFC电堆进行建模是可行的.该LS-SVM模型的建立,对SOFC系统控制策略的研究具有一定的实用价值. 相似文献
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Chandra K Healey G 《Journal of the Optical Society of America. A, Optics, image science, and vision》2007,24(4):957-966
An airborne sensor measures the radiance spectrum, which is dependent on the spectral reflectance of the ground material, the orientation of the material surface, and the atmospheric and illumination conditions. We present an algorithm to estimate the surface spectral reflectance, given the sensor radiance spectrum corresponding to a single pixel. The algorithm uses a nonlinear physics-based image formation model. A low-dimensional linear subspace model is used for the reflectance spectra. The solar radiance, sky radiance, and path-scattered radiance are dependent on the environmental conditions and viewing geometry, and this interdependence is considered by using a coupled-subspace model for these spectra. The algorithm uses the Levenberg-Marquardt method to estimate the subspace model parameters. We have applied the algorithm to a large set of synthetic and real data. 相似文献
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We describe a genetic algorithm approach to solve an inverse problem in optics, which determines the characteristics of a fiber Bragg grating from its reflected spectrum. The validity of the proposed method is demonstrated by use of a Bragg sensor for the measurement of nonlinear strain acting on a uniaxial aluminum test specimen. 相似文献
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提出了一种改进混合蛙跳优化算法,用于改善无线传感网中距离矢量跳段定位算法的精度。首先根据锚节点与未知节点的位置关系利用DV-Hop算法进行初始定位, 然后分析误差来源,将目标定位机制转化为求解非线性总体最小二乘问题。同时合理选择加权因子和适应度函数,并利用带有混沌映射与柯西变异的改进混合蛙跳算法对未知节点坐标进行优化。在实验中,比较了最小二乘法、粒子群算法和改进混合蛙跳算法在定位中的性能。结果显示该智能算法简单可靠,而且有效提高了定位精度。 相似文献
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热膜式空气质量流量传感器动态非线性建模 总被引:1,自引:0,他引:1
热膜式空气质量流量传感器响应速度较快,测量范围宽,可靠性高,广泛应用于发动机空燃比的测量。但是,这种传感器的动态非线性问题影响了进气量测量的精度。采用基于多幅值阶跃信号的Hammerstein模型和两步辨识方法描述了传感器的特性。通过动态标定实验,得到不同幅值的阶跃输入、输出数据。根据幅值,用最小二乘拟合方法确定非线性系数,由输入数据和非线性系数得到静态非线性环节的输出。根据输出数据,运用线性自回归方法得到动态线性环节的传递函数。这样就建立起块联形式的动态非线性模型,有利于传感器动态非线性的校正。建模结果表明,动态非线性模型比线性模型可更准确地描述传感器的特性。 相似文献
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A method was developed for determining the spatial distribution of a source from downward and upward irradiance measurements at a single wavelength in seawater of known optical properties. The algorithm uses measurements at two depths located an arbitrary distance apart and solves two nonlinear equations for two parameters that fit a globally exponential or linear source shape. Complex spatially dependent source shapes can be estimated from an irradiance profile by piecing together estimates from neighboring measurement pairs. Numerical tests illustrate the sensitivity of the algorithm to depth, measurement spacing, chlorophyll concentration, sensor noise, and uncertainty in the a priori assumed inherent optical properties. The algorithm works well with widely spaced measurements, moderate sensor noise, and uncertainties in the optical properties regardless of whether the assumed and true profiles are the same shape. 相似文献
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针对高压力传感器线性化输出的结果不准确的现象,研究了具有针对性的Duffing非线性系统。用传感器的输出数据作为补偿器的输入,传感器的输入数据作为补偿器的输出,进行基于Laguerre函数的非线性动态补偿器的设计研究。该方法无需知道传感器的非线性阶数,对于外界干扰有较强的抑制作用,对于时延对象也具有一定的优势。利用该补偿器对传感器进行动态补偿,将补偿结果与阶跃响应输出进行对比,结果表明该非线性模型补偿的有效性。 相似文献
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Plegge V Slama M Süselbeck B Wienke D Spener F Knoll M Zaborosch C 《Analytical chemistry》2000,72(13):2937-2942
An amperometric biosensor based on immobilized bacterial cells of Alcaligenes eutrophus KT02 and an oxygen electrode was integrated in a flow-through system. Because microorganisms metabolize various organic analytes in a specific manner, the sensor shows for different pure analytes distinct time-dependent oxygen consumption rates that can be treated as characteristic patterns. This behavior is conserved also when the biosensor is exposed to a mixture of these organic analytes; the sensor with a particular type of microorganisms responds with a total signal. The respiration curves as time-dependent amplitudes were subdivided into several time channels. This procedure creates an additional data dimension and makes the single sensor "dynamic". Using multivariate calibration models with only one single biosensor, simultaneous quantitative analysis of ternary mixtures of acetate, L-lactate, and succinate was realized. A nonlinear algorithm that compensated for conceivable interactions of the analytes was superior to a partial least-squares algorithm. Each analyte was predicted more precisely by the nonlinear approach resulting in root-mean-square errors of prediction of 0.20 mg/L for acetate, 0.43 mg/L for L-lactate, and 0.73 mg/L for succinate. 相似文献