共查询到19条相似文献,搜索用时 328 毫秒
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采用《测量不确定度评定与表示指南》,以等离子体发射光谱法测定土壤中的稀土元素铈为例,对测定结果进行不确定度评定。分析了不确定度的重要来源,包括溶液制备过程中引入的不确定度、样品称量引入的不确定度、标准物质外标法测量不确定度及仪器重复测定的不确定度。提供了引入不确定度各参数的采集和计算方法,对各不确定度分量进行分析计算,最后合成标准不确定度,通过乘以95%概率下的扩展因子2,获得测量结果的扩展不确定度。 相似文献
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硅钼黄分光光度法测定地下水中偏硅酸的不确定度评定 总被引:2,自引:1,他引:2
采用不确定度连续传递模型,对硅钼黄分光光度法测定地下水中偏硅酸(DZ/T0064.62—93)的不确定度进行评定。测量结果的不确定度主要来源于标准溶液引入的不确定度、曲线拟合产生的不确定度和测量过程引入的不确定度三部分,而二氧化硅和偏硅酸的摩尔质量不确定度较小,可以忽略不计。采用双误差回归的方式对标准曲线进行拟合,在对各个不确定度分量进行量化的基础上,通过合成得到测量结果的标准不确定度,再乘以95%置信概率下的扩展因子2,得到测量结果的扩展不确定度。 相似文献
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按照测量不确定度评定方法,对氢化物发生-原子荧光光谱法测定地球化学样品中铋结果进行不确定度评定。研究发现原子荧光光谱法测定地球化学样品中铋含量的不确定度主要来源于样品制备过程、标准溶液配制过程、校准曲线拟合过程、重复性测量以及分析仪器的不确定度等。通过对各分量的不确定度进行量化,得出合成标准不确定度和扩展不确定度。结果表明最大的不确定度来源于样品制备过程。当样品中铋含量为24.76μg/g时,其扩展不确定度(k=2)为1.40μg/g。 相似文献
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初期支护与松动圈围岩的协调作用表现出很大的不确定性,其主要影响因素包括:初期支护施工本身导致初期支护的不均匀性,实际围岩的不确定性对初期支护的影响,围岩释放应力的不均匀性导致的初期支护内力分布的不确定性。文章把初期支护的支护和围岩自身自稳能力看成是双介质的承载复合体,采用最小二乘法建立目标函数,结合单纯形算法,进行初期支护与扰动区的联合位移反分析,充分揭示了初期支护与围岩松动圈之间的协调作用;结合实际工程与不考虑初期支护不确定性因素影响的反演分析进行对比,结果显示本文方法反演精度提高39%,预测精度提高了13%。 相似文献
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本文首次提出一个新的研究领域-工程地质量化预测(评价)结论的可靠性分析。文中论述了不确定性的来源、种类和可发现性,初步建立了单种方法预测结论的显著性,多种方法预测的综合结论及其可靠性的一套判别方法。在膨胀土边坡坍塌规模预测中的应用表明使用这套方法能明显地提高预测的准确性。 相似文献
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The CMC (coupled Markov chain) model, which is based on the extension of Markov chains in two-dimensions, is used in the reduction
of uncertainty in geological structures when conditioned (i.e., honours the data and their location) on a number of boreholes.
The model has been applied to an unconsolidated aquifer deposit located in the central Rhine-Meuse delta (the Gorkum study
area) in the Netherlands. A comparison is also made between the CMC and the SIS (sequential indicator simulation) model, which
is based on Kriging and co-Kriging theories on the same deposit. The results show the potential applicability of the CMC model
in reducing the uncertainty in geological configurations when a sufficient number of boreholes is available. Reproduction
of the global geological features requires relatively few boreholes (in this case study, nine boreholes with 30-m spacing
over a distance of 240 m). However, reproduction of the proportion of each state requires a relatively large number of boreholes
(in this case study 31 boreholes with 8-m spacing over a distance of 240 m). It has been shown that variograms can be deceptive
in modeling the spatial pattern and that they reflect only part of the complete spatial structure in the field. The use of
transition probabilities via the CMC model provides a better alternative approach, because it uses multiple point information.
Amro M. M. Elfeki on leave from Department of Irrigation and Hydraulics, Faculty of Engineering, Mansoura University, Mansoura,
Egypt 相似文献
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Uncertainty in the interpretation of geological data is an inherent element of geology. Datasets from different sources: remotely sensed seismic imagery, field data and borehole data, are often combined and interpreted to create a geological model of the sub-surface. The data have limited resolution and spatial distribution that results in uncertainty in the interpretation of the data and in the subsequent geological model(s) created. Methods to determine the extent of interpretational uncertainty of a dataset, how to capture and express that uncertainty, and consideration of uncertainties in terms of risk have been investigated. Here I review the work that has taken place and discuss best practice in accounting for uncertainties in structural interpretation workflows. Barriers to best practice are reflected on, including the use of software packages for interpretation. Experimental evidence suggests that minimising interpretation error through the use of geological reasoning and rules can help decrease interpretation uncertainty; through identification of inadmissible interpretations and in highlighting areas of uncertainty. Understanding expert thought processes and reasoning, including the use of visuospatial skills, during interpretation may aid in the identification of uncertainties, and in the education of new geoscientists. 相似文献
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遥感数据专题分类不确定性评价研究:进展、问题与展望 总被引:7,自引:1,他引:7
从遥感数据中提取专题类别信息是当前遥感数据最主要的应用领域之一。由于遥感分类专题信息广泛应用于各种领域,其数据质量受到越来越多的关注。不确定性是评价分类专题类别数据质量最主要的方面。回顾了遥感数据专题分类不确定性评价方法的历史,总结了当前各种评价方法及其指标体系,将这些方法归结为基于误差矩阵的方法、模糊评价方法、像元尺度上的不确定性评价方法和其它方法四大类。对每一类不确定性评价方法及其指标体系的优点和缺点进行了分析和总结,指出从理论方法研究方面,需要优先发展独立于分类方法的像元尺度上的遥感分类不确定性评价模型与指标体系,以及统一的遥感数据分类不确定性评价模型体系研究;在应用研究方面,需要加强优化空间采样设计和不确定性评价过程标准化研究。 相似文献
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地下水数值模拟不确定性分析旨在提高研究区域地下水流的模拟精度。学者们将地下水数值模拟不确定性分析分为:模型的不确定性、参数的不确定性以及资料的不确定性三类,其中参数的不确定性分析在研究中是最为重要的。同时,对模型、参数、资料不确定性分析的研究进展和成果进行归纳总结,补充关于参数不确定性分析过程中的替代模型的一些研究成果以及模型不确定性分析的多模型分析;强调在地下水数值模拟的过程中,重视模型、资料的不确定性分析;展望未来,随着地下水数值模拟不确定性分析研究的深入,方法和应用会更加多样化。 相似文献
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Uncertainty is ubiquitous in geology, and efforts to characterise and communicate it are becoming increasingly important. Recent studies have quantified differences between perturbed geological models to gain insight into uncertainty. We build on this approach by quantifying differences in topology, a property that describes geological relationships in a model, introducing the concept of topological uncertainty. Data defining implicit geological models were perturbed to simulate data uncertainties, and the amount of topological variation in the resulting model suite measured to provide probabilistic assessments of specific topological hypotheses, sources of topological uncertainty and the classification of possible model realisations based on their topology. Overall, topology was found to be highly sensitive to small variations in model construction parameters in realistic models, with almost all of the several thousand realisations defining distinct topologies. In particular, uncertainty related to faults and unconformities was found to have profound topological implications. Finally, possible uses of topology as a geodiversity metric and validation filter are discussed, and methods of incorporating topological uncertainty into physical models are suggested. 相似文献