查询词典 least squares

On the basis of the power spectra of earthquake records, the parameters of the power spectral density function of the twice filtered Gaussian white noise process are determined by adopting the least squares procedure of a nonlinear function.

根据地震记录的功率谱，采用非线性函数的最小二乘法，确定了两次过滤Gauss白噪声过程的功率谱密度函数的参数。

Least-squares problem of the real symmetric matrices is discussed and the expression of general solution is given.

首先讨论了问题的最小二乘解，给出了解的一般表达式。

Least-squares problem of the real matrices is discussed and the expression of general solution is given.

首先讨论子阵约束下实矩阵反问题的最小二乘问题，给出了解的一般表达式。

Secondly, A MFNN-based nonlinear optimizing controller is designed, which is based on a generalized least squares control cost function.

二、基于广义最小方差控制目标函数，设计了一种基于多层前馈神经网络的非线性优化控制器。

Revised geodesic line method is conducted, by which the cutting patterns analysis are performed. A kind of smoothing method of the least squares is introduced to process the membrane piece in order to satisty the need of accuracy and engineering practice.

提出了一种修正测地线法，利用该方法对薄膜充气构件进行了裁剪分析；引入了一种最小二乘光顺方法，对薄膜裁剪块进行了光顺处理，以便裁剪分析的结果满足精度和工程两方面的需要。

Finally numerical examples with three shape functions are analyzed in detail. The numerical examples show that the modifying generalized moving least squares approximation has high accuracy not only for function value but also one or higher orders derivative.

最后，通过多个数值算例的计算比较了三种形函数的计算结果，结果显示本文提供的MGMLS方法关于函数值和各阶导数值都具有很高的精度。

A simple polynomial approach for A Class of nonlinear system modeling is presented. By this, the input-output data are firstly changed into [0, 1] by using topological homeomorphism conversion; then an initial polynomial model is selected. The parameters of polynomial model are estimated by using recursion least squares method. A final polynomial model is obtained by repeatedly estimating parameter and eliminating redundant terms.

给出一类非线性系统的实现简单的多项式逼近的建模方法，在此方法中，将输入输出数据通过拓扑同胚变换，变换到[0，1]区间内，用多项式逼近的方法进行建模，对初始给定的多项式模型，通过反复的参数辨识、去除模型中的冗余项，得到非线性系统的多项式逼近模型，再利用拓扑反变换，将数据还原回原始数据区间。

The following conclusions have been made in this paper.(1) Based on CO_2 flux data of eddy covariance, variation characteristics of gross primary productivity in four flux observation stations were studied, which are an alpine meadow, an alpine shrub meadow, a swamp alpine meadow and a steppe alpine meadow at Dongxiong. The results show that photosynthetic capacity of the alpine meadow is the highest, and the annual total GPP is 652.2g C/m~2. Daily-differencing approach is used to analyze the random error of CO_2 fluxes measurements. The results show that the distribution of random error follows more closely follows a double-exponential, rather than a normal distribution, capturing the high peak and thick tail, and the random error varies with environment variables, which violates the assumptions for the ordinary least squares fitting with normality and homoscedasticity, consequently, we introduce maximum likelihood method for parameter optimization.

本文主要在以下几个方面开展工作并获得了一些认知和结论：(1)通过分析样带区域内高寒草甸、高寒灌丛、沼泽化湿地和草原化高寒草甸四个通量观测站点草地生态系统总初级生产力变化特征，研究结果表明HBBT矮嵩草草甸生态系统植被光合作用能力较强，年GPP总量为652.2 gC/m~2，明显高于其他三种生态系统；通过利用"单塔日变化法"获得四站点通量观测数据随机误差，结果表明通量观测随机误差概率分布呈现尖峰厚尾的特征，与正态分布相比，更服从双边指数分布，进一步分析表明通量观测随机误差随环境变量(风速、温度和光合有效辐射)的变化而变化，这违背了普通最小二乘法进行生态过程模型参数优化正态分布且误差同质的假设，因此本研究中引入最大似然法进行生态过程模型参数优化。

Tree's volume; biomass; nonlinear least-squares regression; power function model; hyperbolic function model

材积；生物量；非线性最小二乘回归；幂函数模型；双曲函数模型

This can be a least-squares plane or a plane passing through the center of gravity of the corners and is parallel to the mid-rulings of the hyperbolic paraboloid determined by the corners.

这可以是一个最小平方平面或者是一个通过拐角的重心并且平行于由拐点决定的双曲线抛物面的半轴的平面。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。