共查询到19条相似文献,搜索用时 156 毫秒
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《Planning》2016,(15)
为更加准确地探测及处理观测值中的粗差,减少粗差对平差结果的影响,利用抗差估计中一次范数最小法对观测值进行平差处理。采用含有7条水准路线组成的水准网数据作为实验数据,利用Matlab软件,在有、无粗差条件下,分别评估经典间接平差方法与一次范数最小法对数据计算结果的影响。实验结果显示,当某一水准路线中含有200mm的粗差时,利用经典的间接平差法得到的高程与无粗差时得到的高程最大相差了约10cm,而采用一次范数最小法,经过迭代计算,精度有了很大提高。研究表明,一次范数最小法采用权值迭代方法,能够较好地进行粗差探测及处理。 相似文献
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粗差作为一种模型误差,由于其存在的方式不具有统计规律,使得发现和定位粗差具有较大的难度.粗差比偶然误差大得多,它的存在将会严重损害观测数据的质量.本文针对水准网数据,从粗差探测这个方面来探讨和研究水准网粗差探测的方法和思路.本文主要研究的是:在水准网数据处理中,基于稳健估计选权迭代法和数据探测法思想,提出一种改进的IGG法来进行粗差探测,经过实例分析,论证该方法在水准网粗差探测中的优势. 相似文献
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神经网络在GPS向量网抗差估计中的应用分析 总被引:1,自引:0,他引:1
神经网络被引入GPS向量网的平差处理时,网络训练数据由于在测量时各因数的干扰多少都有噪声或异常值掺入。为了使网络具有更好抵抗粗差的能力,文中根据稳健统计有关原理,针对神经网络论证了一种较好的抗差估计函数作为网络目标函数。以函数逼近来说明平差所采用的模型与神经网络处理时的异同,理论分析和实验证明了神经网络的抗粗差能力。 相似文献
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测量数据处理中,稳健估计相较于最小二乘估计有较强的抗粗差能力,本文运用C++编写了一个基于五种不同的稳健估计选权迭代法的CPⅢ高程网平差程序,然后结合某轨道交通工程项目的一段观测的CPⅢ高程数据,通过对比不加粗差和加入粗差时经典最小二乘估计和稳健估计的计算结果,证明该程序的有效性. 相似文献
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为合理确定多源数据的权重,同时为减轻多源观测数据融合过程中观测资料粗差的影响,将抗差方差分量估计引入多源数据融合中。采用山东某煤矿某工作面岩移的初次监测数据进行抗差方差分量估计,以说明多源观测数据融合权比算法的有效性。结果表明,基于抗差方差分量估计确定多源观测数据权重的方法既可以有效地减弱观测资料中粗差的影响,同时可以较好地解决多源观测数据加权的不合理性,提高了数据融合精度。 相似文献
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Andrew Utomi Ebenuwa 《Structure and Infrastructure Engineering》2019,15(3):413-425
This paper presents a numerical strategy for the efficient reliability assessment of engineering structures with random variables and fuzzy variables using fuzzy based optimised subset simulation (SS) approach. The proposed method relies on the performance function of the structure, which involves probability distribution functions and fuzzy variables for the modelling of the structural system. The values of the fuzzy variables for every alpha level are first obtained using the membership function. Therefore, the set values of the fuzzy variable bound the reliability of the structure, and this is evaluated using optimisation and efficient SS approach. The rationale behind the proposed strategy is to locate a failure domain or region where the objective function is minimised or maximised and compute the reliability using SS. The proposed algorithm in this study inherits the benefits of direct Monte Carlo approach in propagating the uncertainties associated with structural parameters but also demonstrate more robustness against the latter. The methodology can be applied to any engineering structures, and the applicability is demonstrated here, using a buried pipeline. 相似文献
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Nang‐Fei Pan 《Construction Management & Economics》2013,31(12):1241-1252
Estimating exact probabilities of occurrence of fault events for use in the conventional fault tree analysis (FTA) is difficult when failure data are insufficient or fault events are imprecise such as human error. A hybrid approach employing fuzzy sets and possibility theory is proposed to overcome this problem. In this approach, failure possibilities of vague events are characterised by fuzzy sets to translate expert subjective judgements while fuzzy fault rates are derived from fuzzy possibility scores based on a transformed Onisawa's possibility function. An example of beam failure illustrates the use of the approach and demonstrates the capability of the model that can assist safety engineers to effectively assess fault possibilities and better evaluate building performance. 相似文献
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针对在GPS高程拟合中可能会因为个别已知高程异常存在粗差导致拟合模型的失真,从而影响转换后的高程精度,采用稳健估计的方法来控制粗差对平差结果的影响,从而有效抵抗粗差的影响。 相似文献
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《Structure and Infrastructure Engineering》2013,9(9):1178-1189
Bridge-pier scouring is a main cause of bridge failures. Thus, accurately predicting the scour depth around bridge piers is critical, both to specify adequate depths for new bridge foundations and to assess/monitor the safety of existing bridges. This study proposes a novel artificial intelligence (AI) model, the intelligent fuzzy radial basis function neural network inference model (IFRIM), to estimate future scour depth around bridge piers. IFRIM is a hybrid of the radial basis function neural network (RBFNN), fuzzy logic (FL), and the artificial bee Cclony (ABC) algorithm. In the IFRIM, FL is used to handle the uncertainties in input information, RBFNN is used to handle the fuzzy input–output mapping relationships, and the ABC search engine employs optimisation to identify the most suitable tuning parameters for RBFNN and FL based on minimal error estimation. A 10-fold cross-validation method finds that the IFRIM model achieves at least 21% and 14.5% reductions in root mean square error and mean absolute error values, respectively, compared with other AI techniques. Study results support the IFRIM as a promising new tool for civil engineers to predict future scour depth around bridge piers. 相似文献
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基于模糊推理的公共交通分担率预测研究 总被引:5,自引:0,他引:5
研究基于模糊推理建立公共交通分担率预测模型的方法。通过分析公共交通出行的影响因素,选择线网密度、国内生产总值、平均车速等十项指标作为影响因素,建立模糊层次结构模型。确定各因素的模糊规则,采用模糊推理预测公交分担率。并以黑龙江省某市交通数据进行预测,最后分析了影响因素与分担率水平的影响关系,应用得到了预期的效果。 相似文献
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以厦门岛内具有代表性的153个钻孔试验数据为基础,依据模糊综合评判理论,建立了砂土液化的评判模型,该模型以层次分析法确定因子权重,分别构造了各评价因子的隶属度函数,将该方法与规范法评判结果进行比较,获得较好评判结果。 相似文献
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