共查询到20条相似文献，搜索用时 156 毫秒
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一种更好的曲线回归方法 总被引：1，自引：0，他引：1
王汉文 《湖北大学成人教育学院学报》2002,20(3):75-76
我们在学习《数理统计》这门功课的回归分析这章时，对于y=a bx这样的线性模型时，毫无疑问我们用最小二乘法，即建立目标函数Q=∑(yi-yi)^2，使之最小，从而求出a、b。对于非线性模型我们的办法是先将其线性化，然后再模拟直线回归方法建立目标函数，使其最小求出非线性模型的参数，这种方法的确能很简便的拟合出一个非线性模型。 相似文献
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Logistic种群增长模型参数的生态学意义及其辨识──南湾野生猕猴种群的应用 总被引：2，自引：0，他引：2
通过分析Logistic模型的推导过程得到了各个参数之间的关系，这些参数包括种群增长率r，环境容纳量K，密度制约系数l，常数项a，拐点时刻rm.并且进一步阐明了参数的生态学意义（定义）与统计学意义（即统计估计所得的参数值）的不一致.表明常用的线性与非线性回归所求得的参数并不能代表其真实的生态学意义．本文以海南南湾野生猕猴的种群增长曲线为例，偿试了一种新的方法通过对捕促猴行为的不同处理引起的Logistic非线性回归曲线的不同反应的分析，并结合参数之间固有关系，得到了不同于回归方法所求得的参数值 相似文献
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我国原煤产量的部分线性自回归预测模型 总被引：1，自引：0，他引：1
针对传统的原煤产量预测模型不能理想地捕获我国煤炭产量的非线性性特征,本文基于核估计半参数理论,对我国原煤产量的月度数据建立了部分线性自回归模型,并对2007上半年的月原煤生产量进行了预测,计算结果表明,相对于参数自回归模型而言,部分线性自回归模型能够很好地解决原煤产量预测这一非线性问题,预测精度较高。 相似文献
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以天然麦壳为吸附剂,研究了温度和浓度对麦壳吸附水溶液中亚甲基蓝(MB)的影响.随着MB平衡浓度的增加,麦壳对MB的吸附量增加,升高温度有利于吸附.根据Langmuir模型的线性形式和非线性形式,采用最小盖方和方法.用线性回归分析和非线性回归分析方法,得到了模型的参数.结果表明,线性分析和非线性分析都可用于平衡浓度对麦壳吸附MB的影响. 相似文献
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本文的主要研究分为三大部分,第一部分为非线性回归模型的知识,主要包括非线性回归的定义,非线性回归模型的定义,以及它的理论分析;第二部分主要为非线性回归模型参数估计的方法,本文主要探讨非线性回归模型参数估计、最大似然估计和拟似然估计这三种方法;第三部分主要讲述非线性回归模型参数估计的应用实例.这些算法通过对问题的解空间交替进行全局和局部搜索,达到快速收敛至全局最优解. 相似文献
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李晓康 《廊坊师范学院学报(自然科学版)》2014,(3):8-11
根据基金净值样本数据的尾部特点,运用POT方法确定临界值,运用非线性回归方法给出参数的最小二乘估计,建立极大值分布的GPD模型,并对模型进行了检验,最后,运用建立的模型对一些极值点进行预测,结果较为理想. 相似文献
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Excel在实验数据回归分析中的应用 总被引：2，自引：3，他引：2
介绍了Excel在数据回归中的应用方法，重点介绍了非线性模型回归的方法．无需编程即可准确快捷地得到计算结果。这种方法可用于教学和工程计算。 相似文献
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黄昕龙花海燕陈世辉 《福建工程学院学报》2020,(6):524-529
产品的表面质量差严重制约了熔融沉积成型(fused deposition modeling,FDM)工艺的发展,通过粗糙度成型机理构建参数模型是提升FDM 成型件表面质量的重要途径。文章以某FDM 打印设备成型件的水平表面粗糙度为例,通过探讨参数三次曲线与多段直线拟合的丝宽模型,利用粗糙度的几何机理提出了基于3 个主要工艺参数的回归模型,采用样条变换的非线性偏最小二乘回归(partial least squares,PLSR)建立对所选参数的有效预测模型,并对建模中未覆盖的不同打印参数下的实验数据样本进行校验,分析工艺参数对水平表面粗糙度的影响。通过以上研究方法,提高了水平表面粗糙度预测效率,获取了相关的经验知识。 相似文献
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统计过程控制是过程监控与故障诊断的方法。在多变量统计过程控制中,传统的方法主要包括主元分析和偏最小二乘,这些方法存在着诸多缺陷。设计时可以应用非线性主元分析、非线性偏最小二乘、动态主元分析、自适应主元分析、多尺度主元分析等方法进行改进。研究中要重视带噪声的监控模型、过程模型信息与经验知识相结合等问题,同时可以把一些新的降维技术用于统计过程控制中。 相似文献
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HUANG Jian GUAN Zhihong WANG Zhongdong Department of Control Science & Engineering Huazhong University of Science & Technology Wuhan Hubei P.R. China 《重庆大学学报(英文版)》2004,3(1):30-33
1.IntroductionAsthecomplexityofmoderncontrolsystems,itsdimensionbecomesmoreandmorevast.Actuators,sensorsandcontrollersinsystemsareusuallydistributed.Theclose-loopfeedbackcontrolsystemscanbeestablishedviaconnectingthesenodeswithcommunicationnetwork.Thesesystemsareoftencallednetworkedcontrolsystems(NCSs).TheNCSsbasedonfieldbusnetwork,suchasCANbus,havebeenwidelyusedinvariousindustrialareasinrecentyears.Therearemanynewissueswhenusingnewsystems.Thefirstissueisthenetwork-induceddelay(sensor-to-… 相似文献
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W. Holmes Finch Maria E. Hernández Finch Brooke Avery 《Learning disabilities research & practice》2023,38(2):104-118
Progress monitoring using curriculum-based measures administered to a student at multiple points in time is common in educational settings. Recent research has demonstrated that common approaches to identifying individuals in need of special services, such as the trend line or median techniques, can be negatively impacted by the nonlinear change in scores over time. The purpose of this study was to test and demonstrate a nonlinear regression model for adjusting the linear trend line for the presence of such nonlinearities, thereby improving the accuracy of common methods for identifying students in need of special services. Results demonstrated that use of this nonlinear model improved the accuracy of common methods for identifying students in need of special services. 相似文献
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An extension of two confirmatory factor models for multitrait-multimethod measurement designs with structurally different methods to the analysis of latent interaction effects is presented: the nonlinear latent difference (NL-LD) model and the nonlinear correlated trait–correlated method-minus-one (NL-CTC[M – 1]) model. Both models are compared with regard to (a) the psychometric definition of the latent variables, (b) the capabilities of explaining latent method effects, and (c) the analysis of latent interaction effects. Using the latent moderated structural equation approach, we show how moderated method effects can be examined in the NL-CTC(M – 1) model. This fine-grained analysis of method effects is not feasible using the classical NL-LD model. We propose an extended version of the NL-LD model, which recovers the results of the NL-CTC(M – 1) model. The different versions of the nonlinear multimethod models are illustrated using real data from a multirater study. Finally, the advantages and challenges of incorporating latent interaction effects in complex CFA–MTMM models are discussed. 相似文献
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In this paper, a nonlinear dynamic MIMO model of a 6-DOF underactuated quad rotor rotorcraft is derived based on Newton-Euler formalism. The derivation comprises determining equations of motion of the quad rotor in three dimensions and seeking to approximate the actuation forces through modeling of the aerodynamic coefficients and electric motor dynamics. The derived model is dynamically unstable, so a sequential nonlinear control strategy is implemented for the quad rotor. The control strategy includes exact feedback linearization technique, using the geometric methods of nonlinear control. The performance of the nonlinear control algorithm is evaluated using simulation and the results show the effectiveness of the proposed control strategy for the quad rotor rotorcraft near quasi-stationary flight. 相似文献
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W. Holmes Finch 《Structural equation modeling》2013,20(1):60-75
Researchers have devoted some time and effort to developing methods for fitting nonlinear relationships among latent variables. In particular, most of these have focused on correctly modeling interactions between 2 exogenous latent variables, and quadratic relationships between exogenous and endogenous variables. All of these approaches require prespecification of the nonlinearity by the researcher, and are limited to fairly simple nonlinear relationships. Other work has been done using mixture structural equation models (SEMM) in an attempt to fit more complex nonlinear relationships. This study expands on this earlier work by introducing the 2-stage generalized additive model (2SGAM) approach for fitting regression splines in the context of structural equation models. The model is first described and then investigated through the use of simulated data, in which it was compared with the SEMM approach. Results demonstrate that the 2SGAM is an effective tool for fitting a variety of nonlinear relationships between latent variables, and can be easily and accurately extended to models including multiple latent variables. Implications of these results are discussed. 相似文献
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利用MATLAB编程软件,分别建立BP神经网络和AR模型,采用全国出生率,死亡率,老年抚养率等9个指标作为样本,分别对BP网络和AR模型进行训练,预测5年后的人口数量.结果表明这两种方法预测人口均是可行的,效果较好,误差很小,但是AR模型较适合线性预测,而BP网络适合较非线性预测. 相似文献
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本文讨论一类用多项式型描述的非线性系统的分析和辨识问题。首先,利用不动点理论建立了这一类非线性反馈系统的迭代格式和输入输出稳定性判据;其次,得到了一种非线性系统的有效辨识方法,这种方法可用快速Fourier技术实现。 相似文献
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A novel model of fuzzy clustering using kernel methods is proposed. This model is called kernel modified possibilisticc-means (KMPCM) model. The proposed model is an extension of the modified possibilistic c-means (MPCM) algorithm byusing kernel methods. Different from MPCM and fuzzy c-means (FCM) model which are based on Euclidean distance, theproposed model is based on kernel-induced distance. Furthermore, with kernel methods the input data can be mappedimplicitly into a high-dimensional feature space where the nonlinear pattern now appears linear. It is unnecessary to docalculation in the high-dimensional feature space because the kernel function can do it. Numerical experiments show thatKMPCM outperforms FCM and MPCM. 相似文献
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建立了电机转子机电耦联的非线性数学模型 ,研究了由电磁力激发的参数振动非线性系统的响应曲线 ,揭示了各种电磁参数及机械参数对共振的影响 .结果表明 ,系统在电磁力作用下存在着 1/2亚谐共振的条件 ,电磁力对稳定区域有明显影响 ,且其线性项和非线性项均能激发参数共振 .同时建立了机电耦联问题的电机系统的稳定性条件 ,并得到了参数域中的稳态共振曲线和运动状态 ,所揭示的动力学现象为定性地控制电机的稳定运行状态提供了理论依据 相似文献