排序方式： 共有10条查询结果，搜索用时 15 毫秒
1
1.
利用最小二乘配置进行地壳形变分析,其结果的合理性关键在于经验协方差函数的拟合.考虑到观测数据存在粗差的情况,提出基于观测值中位数初值的抗差最小二乘配置方法和基于中位参数法的抗差最小二乘配置方法.两种方法首先分别利用观测值中位数给出观测值初始权阵以及利用中位参数法给出最小二乘配置初始解,然后均在给定协方差函数参数初始值的情况下,应用合适的等价权进行抗差估计并通过迭代计算,最终获得稳健的协方差函数参数估值及最小二乘配置解.利用本文提出的两种方法以及传统方法分别对庐山地震的GPS垂直位移数据和意大利L'Aquila地震的InSAR同震位移数据进行处理分析.结果表明:相对传统方法,基于观测值中位数初值的抗差最小二乘配置方法效果更好,更具稳健性. 相似文献
2.
抗差卡尔曼滤波模型及其在GPS监测网中的应用 总被引：16，自引：0，他引：16
根据量测向量中的粗差对状态向量滤波值的影响规律，导出了抗差卡尔曼滤波模型，该模型对观测空间和设计空间均具有良好的抗差性。通过对含有粗差的模拟GPS监测网的计算，与标准卡尔曼滤波模型相比较，利用该抗差滤波模型，可获得可靠的变形分析结果。 相似文献
3.
TUTORIAL TO ROBUST STATISTICS 总被引：1，自引：0，他引：1
PETER J.ROUSSEEUW 《地理学报(英文版)》1991,(1)
The least squares method 15 eurrently the most PoPular aPProaeh to estimation beeause oftradition and ease of eomPutation,However,real data sets frequently eontain outliers,whiehmay be mistakes or exeePtional observations.In this situation least squares beeomesunreliable.Two things often haPPen:the estimates become 相似文献
4.
Laura E. Beramendi-Orosco Galia Gonzalez-Hernandez Linda R. Manzanilla Avto Goguitchaishvili 《Quaternary Research》2009,71(2):99-107
A high-resolution 14C chronology for the Teopancazco archaeological site in the Teotihuacan urban center of Mesoamerica was generated by Bayesian analysis of 33 radiocarbon dates and detailed archaeological information related to occupation stratigraphy, pottery and archaeomagnetic dates. The calibrated intervals obtained using the Bayesian model are up to ca. 70% shorter than those obtained with individual calibrations. For some samples, this is a consequence of plateaus in the part of the calibration curve covered by the sample dates (2500 to 1450 14C yr BP). Effects of outliers are explored by comparing the results from a Bayesian model that incorporates radiocarbon data for two outlier samples with the same model excluding them. The effect of outliers was more significant than expected. Inclusion of radiocarbon dates from two altered contexts, 500 14C yr earlier than those for the first occupational phase, results in ages calculated by the model earlier than the archaeological records. The Bayesian chronology excluding these outliers separates the first two Teopancazco occupational phases and suggests that ending of the Xolalpan phase was around cal AD 550, 100 yr earlier than previously estimated and in accordance with previously reported archaeomagnetic dates from lime plasters for the same site. 相似文献
5.
W. G. Strupczewski K. Kochanek S. Weglarczyk V. P. Singh 《Stochastic Environmental Research and Risk Assessment (SERRA)》2005,19(4):280-291
Robustness of large quantile estimates to the largest element in a sample of methods of moments (MOM) and L-moments (LMM) was evaluated and compared. Quantiles were estimated by log-logistic and log-Gumbel distributions. Both are lower bounded and two-parameter distributions, with the coefficient of variation (CV) serving as the shape parameter. In addition, the results of these two methods were compared with those of the maximum likelihood method (MLM). Since identification and elimination of the outliers in a single sample require the knowledge of the samples parent distribution which is unknown, one estimates it by using the parameter estimation method which is relatively robust to the largest element in the sample. In practice this means that the method should be robust to extreme elements (including outliers) in a sample.The effect of dropping the largest element of the series on the large quantile values was assessed for various coefficient of variation (CV) / sample size (N) combinations. To that end, Monte-Carlo sampling experiments were applied. The results were compared with those obtained from the single representative sample, (the first order approximation), i.e., consisting of both the average values (Exi) for every position (i) of an ordered sample and the theoretical quantiles based on the plotting formula (PP).The ML-estimates of large quantiles were found to be most robust to largest element of samples except for a small sample where MOM-estimates were more robust. Comparing the performance of two other methods in respect to the large quantiles estimation, MOM was found to be more robust for small and moderate samples drawn from distributions with zero lower bound as shown for log-Gumbel and log-logistic distributions. The results from representative samples were fairly compatible with the M-C simulation results. The Ex-sample results were closer to the M-C results for smaller CV-values, and to the PP-sample results for greater CV values. 相似文献
6.
滑坡位移预测预报是滑坡防灾减灾的重要组成部分,提高滑坡位移预测的准确性与精确度是该项研究的重点与难点。本文在滑坡位移预测中考虑了监测样本的离群值,通过忽略、指定与修正离群值3种方式,研究滑坡位移预测样本离群值的最优处理方式。以三峡库区朱家店滑坡为例,基于ARIMA(p,d,q)模型,分别对累积位移与位移速率时间序列开展了预测研究。研究结果表明:修正离群值的预测结果介于忽略和指定离群值两者之间,更适用于存在监测离群值的滑坡位移预测;对于ARIMA模型,更适合采用位移速率进行预测预报;使用位移速率时间序列ARIMA(1,0,1)并修正离群值的预测结果为:2016年和2017年6月份滑坡前缘GP3"阶跃"位移分别为79. 0 mm和70. 2 mm,截止2017年8月,GP3累积位移将达1647. 7 mm。 相似文献
7.
通过本站出现的异常值实例进行分析,对经质量控制后系统自动生成的疑误信息进行人工判断,并结合有关技术规定和问题解答给予适当处理,以确保净全辐射观测数据的真实、可靠。 相似文献
8.
PHILIP J. BROWN Department of Statistics Computational Mathematics University of Liverpool PO Box Liverpool L BX U. K. 《地理学报(英文版)》1993,(4)
Modern scanning infrared reflectance/absorption spectroscopes measure absorptions or reflectance at asequence of around 1000 wavelengths. Training data may consist of 10-100 carefully designed samplemixtures whose true compositions are either known by formulation or accurately determined by wetchemistry. In future, one wishes to predict the true composition of a newly presented sample from itsspectrum. Varying compositions of a mixture of three sugars in water are used for illustration of severaldifferent graphical techniques; the spectral measurements here are near-infrared (NIR) absorbances, butthere is nothing exclusively infrared about the methodology. Graphs display the adequacy of a linearexplanation of absorbance variability at each wavelength by wavelength linearity plots. These highlightregions of the spectrum where non-linearities and interaction effects are substantial. By selecting out thesesubstantially non-linear regions, one can concentrate on linear formulae for prediction with resultantrobust linear modelling. Such selections are further aided by plots which identify the component sugarfor which each wavelength is most selective. Such plots offer rather natural pre-screening as an alternativeor supplement to the wavelength selection method of Brown. We also display prediction diagnostics (R, Rx) which on a sample-by-sample basis may diagnose aparticularly unusual presented spectrum. These diagnostics are shown to have predictive import for avalidation data set. 相似文献
9.
动态系统的抗差Kaliman滤波 总被引：9，自引：0，他引：9
离散历元的动态观测量及其相应的动态模型可能存在异常，若数据处理模型不考虑对这些异常的特别处理，则动态模型参数估值及其所提供的动态信息将极不可靠。基于贝叶斯统计和抗差估计原理，我们构造了一种抗差滤波算法。该算法考虑观测分布和参数验前分布均为污染分布。并利用一个实测网验算该算法和模型的可靠性。 相似文献
10.
Minimal detectable biases of GPS data 总被引：4，自引：1，他引：3
P. J. G. Teunissen 《Journal of Geodesy》1998,72(4):236-244
In this contribution closed-form expressions are given for the minimal detectable biases of single- and dual-frequency pseudo-range
and carrier-phase data. They are given for three different single-baseline models. These are the geometry-free model and two
variants of the geometry-based model, namely the roving and stationary variants. The baselines are considered to be sufficiently
short such that orbital uncertainties in the fixed orbits and residual ionospheric and tropospheric delays can be assumed
absent. The stochastic model used is one that permits cross-correlation and the use of different variances for individual
GPS observables, including the possibility to weigh the observables in dependence on which satellite is tracked.
Received: 23 April 1997 / Accepted: 27 October 1997 相似文献
1