查询词典 estimation of error

Since both of them are approximate solutions, attention to the estimation of error has to be paid.

由于这两种解法得到的都是近似解，因此近似解的误差不能不让人关注。

By means of analyzing the noise error, it is proposed to use an algorithm of singular value decomposition total least squares to conduct the interharmonics estimation, namely taking the noise interference at both sides of the matrix equation into account simultaneously and solving the minimum norm problem by least square method under such condition. In the proposed algorithm by means of singular value decomposition of a new augmented matrix and by use of a simple and practical method to determine the number of principal singular value related to signal to noise ratio, the storage calculation of right singular matrix is performed, thus a more accurate frequency estimation of interharmonics can be obtained.

通过分析噪声误差，提出采用奇异值总体最小二乘(singular value decomposition total least squares，SVDTLS)算法进行间谐波频率估计，即同时考虑矩阵方程两边的噪声干扰，采用SVDTLS算法求解该情况下的最小范数解，通过对增广矩阵进行奇异值分解(singular value decomposition，SVD)，采用简单实用的与信噪比相关的主奇异值个数确定方法对分解的右奇异矩阵进行存储计算，得到了较精确的间谐波频率估计结果。

The common method, that all strong-correlation terms of the model are eliminated, can bring the loss in the engineering application, so the new method is proposed that the identified model reserves some correlation. The augmented matrix A is constructed by the outputΔW and the matrix S. The"determinating order based on ratio of determinant"is brought out to screen the strong-correlation terms in the structure identification. The latent root estimation is improved in screening the eigenvalues and eigenvectors. Thus the estimation precision is improved greatly.The consistence check of guidance instrument error coefficients of flight test and ground test is the purpose of flight experiment. The causes of inconsistency of the two models are analyzed. The hypothesis test of linear regression model based on F statistics is proposed to check the consistence.Finally, the instability of error coefficients is probably caused by the change of the flight environments, therefore, the relation between the error coefficients and flight environment is analyzed. The approach is presented to identify SINS guidance instrument error models and compensate the error in the segmented sections corresponding to the change of vertical acceleration of aircraft.

在结构辨识中，常用的方法由于将模型中的强相关项全部剔除而给工程应用带来损失，因此，本文提出了新的有益思想，即在保留一定相关性的基础上进行辨识：将输出向量ΔW与环境函数矩阵S构成增广矩阵A，然后采用"比定阶行列式"来剔除相关向量的方法，这样既可以尽可能多地保留了对落点影响大的强相关参数，又可以对落点影响小的强相关参数给予剔除；在参数估计中，改进了特征根估计中特征根和特征向量的筛选方法，提出"近零"准则，从而大大提高了参数估计的精度；再者，鉴于天地模型"一致性"检验是飞行试验和SINS制导工具误差系数分离的主要目的，因此，本文又深入分析了造成天地模型不一致的原因，提出了采用基于F统计的线性回归模型假设检验方法来进行捷联制导工具误差模型的天地"一致性"检验；最后，鉴于飞行环境剧烈变化可能会对惯性仪表误差系数稳定性带来一定的影响，因此本文深入地分析了SINS制导工具误差系数与外界环境的关系，提出了基于过载变化大小的分段辨识和分段实时补偿的算法。

For fitting ROC curves and getting the area under the ROC curve, we applied the parametric methods of binormal models and ordinal regression models, the semiparametric method of Cox proportional hazards model, the nonparametric methods of Hanley, Delong This paper also include estimation of required sample size, evaluation of confounding effects, and estimation of standard error and confidence interval by resampling method for ROC analysis.

目前该模型用于ROC分析的统计学方法比较完善，属于"经典"的ROC分析参数法。本文探讨了单变量、双变量双正态ROC模型的构建及其参数的最大似然估计方法；采用双变量卡方检验、真阳性率z检验、面积z检验三种方法比较了ROC曲线间是否具有显著性差异。

The adaptive program is calculated by T-B stress recovery scheme and z-z error estimation, the error is estimated by energy norm of difference of recovery stress and meshless stress. If the local relative error exceeds the limit relative error, then new nodes will be generated at the high error area.

本研究的自适应方法采用TB应力平滑技术和Z-Z误差估计，利用平滑应力和无网格法所得应力解差值的能量范数来估算误差，如果局部相对误差超过了允许误差，则在高误差域插入新的离散点进行加密。

Based on the analysis and summary of basic ideas and methods,this thesis proposes two new estimation of error of higher order approximation.

方法二是在等距分布的条件下，基于三次样条插值函数的三弯距算法，通过利用节点处弯距的加权和近似计算区间中点处的二阶导数。

As a differential detection is used between the intercarrier, the proposed algorithm overcome the high sensitivity to timing error of conventional algorithm and is robust to multi-path. The effect of sample frequency offset can't be ignored in a continuous OFDM system of a large number of subcarriers. The estimation precision of the conventional algorithm is low and the realization is complex. A joint estimation of sample frequency offset and fine frequency offset based on difference operation is proposed. As averaging use a large number of samples in a maximum likelihood algorithm, the estimation precision is very high. The use of difference operation cancel the effect of carrier frequency offset, and the proposed sampling frequency estimation algorithm is robust to carrier frequency offset.

最后，本文对连续系统中的采样频率和载波频率精同步技术进行较为深入的研究，由于子载波数目大的连续OFDM传输系统中，采样频率偏差不可忽视，以往的采样频率估计方法精度低、实现复杂，因此本文提出了一种基于差分处理的采样频率偏差和精载波频率偏差联合估计算法，利用了最大似然算法进行采样频率偏差的估计，由于采用了差分处理方法，消除了载波频率偏差对采样频率偏差估计的影响，采用的最大似然算法对大量样点进行平均化处理，所以，相对以往算法，提出的联合算法估计精度高，而且采样频率偏差估计对载波频率偏差具有鲁棒性。

The error of ultimate load prediction after retrofitting:the error of structure program and preliminary estimation are between respectively 35~80% and 25~40%, the reason of error results from the slight deformation between the fixed beam relation with brick arch and reaction force base.

砖拱补强后，其水平极限荷载预测之误差：值分析程式预测结果误差约在35~80%之间，推估公式预测结果误差约在25~40%之间，试验进时砖拱与底固定处及底与反基座产生微小变形应为误差源。

The estimation of forming part"s sideline The estimation of forming part"s sideline is significant in weld and assembly process, the paper puts forth two kinds of method to realize quantitative analysis for the deformed sideline, one is using line contour error to estimate deformed sideline combined with GA and taking the value of line contour error as target to check whether it is in the range of precision; The other is comparing curvature and torsion of design model with curvature and torsion of deformed model to check the sidelines precision.

冲压件边线变形的评价。冲压件的边线变形的评价在焊装工艺中有着重要意义，本文提出两种方法来实现冲压件边线的变形评价：一是借鉴线轮廓度评定的方法，结合遗传算法计算出边线的线轮廓度，并以线轮廓度值作为边线是否满足要求的评价指标：二是通过比较变形前后曲线的曲率和挠率来评价边线的变形情况。

First, this section analyzes the error drifts in bit rate adaptation transcoding, including error drift caused by motion re-estimation and error drift of the pixel-domain transcoding compared with the compressed transcoding.

首先，分析了码率调整型转码算法中存在的若干错误漂移问题：运动估计带来的错误漂移；相对于压缩域转码器，像素域转码器的错误漂移。

It is also known as one of the most poisonous naturally occurring substances.

它也被称为一个最自然发生的有毒物质。

The greatest stress is found at the location on the cross section where V is the largest.

最大应力出现在横截面上V为最大的地方。