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A new method of estimating the ratio between in situ rock stresses and tectonics based on empirical and probabilistic analyses 总被引：1，自引：0，他引：1
This paper describes a new procedure for assessing the ratio between in situ stresses in rock masses by means of K (K = σH / σv, being σH and σv principal stress) and tectonics for purposes of engineering geology and rock mechanics. The method combines the use of the logic decision tree and the empirical relationship between the Tectonic Stress Index, TSI, and a series of K in situ values obtained from an extensive database. The decision tree considers geological and geophysical factors affecting stress magnitudes both on the regional and local scale. The TSI index is defined by geological and geomechanical parameters. The method proposed provides an assessment of the magnitude of horizontal stresses of tectonic origin. Results for several regions of Europe are presented and the possible applications of the procedure are discussed. 相似文献
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G.?ChristakosEmail author 《Stochastic Environmental Research and Risk Assessment (SERRA)》2003,17(5):276-290
We suggest a critical look at the epistemic foundations of the porous media upscaling problem that focuses on conceptual processes at work and not merely on form manipulations. We explore the way in which critical aspects of scientific methodology make their appearance in the upscaling context, thus generating useful effective parameters in practice. The fons et origo of our approach is a conceptual blending of knowledge states that requires the revision of the traditional method of scientific argument underlying most upscaling techniques. By contrast to previous techniques, the scientific reasoning of the proposed upscaling approach is based on a stochastic model that involves teleologic solutions and stochastic logic integration principles. The syllogistic form of the approach has important advantages over the traditional reasoning scheme of porous media upscaling, such as: it allows the rigorous derivation of the joint probability distributions of hydraulic gradients and conductivities across space; it imposes no restriction on the functional form of the effective parameters or the shape of the probability laws governing the random media (non-Gaussian distributions, multiple-point statistics and non-linear models are automatically incorporated); it relies on sound methodological principles rather than being ad hoc; and it offers the rational means for integrating the multifarious core knowledge bases and uncertain site-specific information sources about the subsurface system. Previous upscaling results are derived as special cases of the proposed upscaling approach under limited conditions of porous media flow, a fact that further demonstrates the generalization power of the approach. Our hope is that looking at the upscaling problem in this novel way will direct further attention to the methodological exploration of the problem at the length and the detail that it deserves.I would like to thank Drs. A. Kolovos and D.T. Hristopulos for their valuable comments. The work was supported by grants from the Army Research Office (Grant no. DAAG55–98–1-0289) and the National Institute of Environmental Health Sciences (P42-ES05948 & P30-ES10126). 相似文献
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The use of logic trees in probabilistic seismic hazard analyses often involves a large number of branches that reflect the uncertainty in the selection of different models and in the selection of the parameter values of each model. The sensitivity analysis, as proposed by Rabinowitz and Steinberg [Rabinowitz, N., Steinberg, D.M., 1991. Seismic hazard sensitivity analysis: a multi-parameter approach. Bull. Seismol. Soc. Am. 81, 796–817], is an efficient tool that allows the construction of logic trees focusing attention on the parameters that have greater impact on the hazard.In this paper the sensitivity analysis is performed in order to identify the parameters that have the largest influence on the Western Liguria (North Western Italy) seismic hazard. The analysis is conducted for six strategic sites following the multi-parameter approach developed by Rabinowitz and Steinberg [Rabinowitz, N., Steinberg, D.M., 1991. Seismic hazard sensitivity analysis: a multi-parameter approach. Bull. Seismol. Soc. Am. 81, 796–817] and accounts for both mean hazard values and hazard values corresponding to different percentiles (e.g., 16%-ile and 84%-ile). The results are assessed in terms of the expected PGA with a 10% probability of exceedance in 50 years for rock conditions and account for both the contribution from specific source zones using the Cornell approach [Cornell, C.A., 1968. Engineering seismic risk analysis. Bull. Seismol. Soc. Am. 58, 1583–1606] and the spatially smoothed seismicity [Frankel, A., 1995. Mapping seismic hazard in the Central and Eastern United States. Seismol. Res. Lett. 66, 8–21]. The influence of different procedures for calculating seismic hazard, seismic catalogues (epicentral parameters), source zone models, frequency–magnitude parameters, maximum earthquake magnitude values and attenuation relationships is considered. As a result, the sensitivity analysis allows us to identify the parameters with higher influence on the hazard. Only these parameters should be subjected to careful discussion or further research in order to reduce the uncertainty in the hazard while those with little or no effect can be excluded from subsequent logic-tree-based seismic hazard analyses. 相似文献
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以黑河山区为研究区域,利用Logic回归模型和空间分析技术对山区土地利用进行适宜性评价.以2011年土地利用现状数据作为背景值,构建气温、降水、海拔、坡度、人口密度、水系、交通网、村镇分布8种因子的评价指标体系.采用多尺度训练的方法确定适宜性评价最佳模拟尺度,对土地利用数据和评价因子进行Logic回归分析,得到评价因子对土地利用适宜性的影响程度.利用Spatial Analyst模块对对黑河山区土地适宜性进行评价,为区域土地资源合理利用提供科学参考.结果表明：（1）适宜性评价最佳尺度为210 m（ROC=0.79）.（2）Logic回归结果显示,坡度、气温（βTemp=1.11）、降水对林地、草地的影响程度较高,同时距道路距离、人口密度（βPop=-0.555）对其分布也有重要影响.（3）山区土地利用适宜性排序为：Max林地=Max耕地 > Max建设用地 > Max裸地 > Max草地 > Max水域,林地与耕地最高,适宜性达到0.99. 相似文献
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Samuel Kinsley 《Geoforum》2011,42(2):231-240
Visions of the future predict spaces apparently teaming with ever more novel and pervasive technologies. Significant amongst such forecasts is the notion of ‘ubiquitous computing’ (ubicomp), understood as an affordance or capacity tied (in)to people, places and things. This article stages an encounter between the futurity of ubicomp and recent debates in geography around anticipation. So, first, the future orientation in ubicomp research and development (R&D) is investigated as a mode of anticipation. ‘Knowledges’, and ‘logics’ of anticipation are subsequently, and second, discussed as the conceptual apparatus that constructs and perpetuates the ‘proximate future’ of ubicomp. This analysis connects recent discussion about ‘anticipation’ in social sciences research with the methods of ubicomp research, which fits with an emergent agenda around futurity in human geography. Third, the conceptual articulation of ‘anticipatory logic’ is applied to the analysis of empirical investigations of ubicomp R&D to identify the specific logics of anticipation at play. This article accordingly examines the logics of anticipation that both support and destabilise the certainty with which the future is imagined within ubicomp. In conclusion, the multiple ways of anticipating a future world and the ways in which they discipline understandings of futurity are framed as a politics of anticipation. 相似文献
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VVVF变频器在电梯系统改造中的应用 总被引：1，自引：0，他引：1
采用交流变频调速器（ＶＶＶＦ变频器）对继电器控制方式的电梯（如：交流双速梯、交流调整梯、直流梯等）进行改造,对改善电梯的运行性能、社会性能、乘坐舒适感、节能等方面有极大的优越性,代表了当今电梯系统改造的主流方向,本文介绍了ＶＶＶＦ变频器在高层电梯系统改造中的实际应用。 相似文献
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Seismic hazard assessment of the Province of Murcia (SE Spain): analysis of source contribution to hazard 总被引：1，自引：0，他引：1
A probabilistic seismic hazard assessment of the Province of Murcia in terms of peak ground acceleration (PGA) and spectral
accelerations [SA(T)] is presented in this paper. In contrast to most of the previous studies in the region, which were performed for PGA making
use of intensity-to-PGA relationships, hazard is here calculated in terms of magnitude and using European spectral ground-motion
models. Moreover, we have considered the most important faults in the region as specific seismic sources, and also comprehensively
reviewed the earthquake catalogue. Hazard calculations are performed following the Probabilistic Seismic Hazard Assessment
(PSHA) methodology using a logic tree, which accounts for three different seismic source zonings and three different ground-motion
models. Hazard maps in terms of PGA and SA(0.1, 0.2, 0.5, 1.0 and 2.0 s) and coefficient of variation (COV) for the 475-year
return period are shown. Subsequent analysis is focused on three sites of the province, namely, the cities of Murcia, Lorca
and Cartagena, which are important industrial and tourism centres. Results at these sites have been analysed to evaluate the
influence of the different input options. The most important factor affecting the results is the choice of the attenuation
relationship, whereas the influence of the selected seismic source zonings appears strongly site dependant. Finally, we have
performed an analysis of source contribution to hazard at each of these cities to provide preliminary guidance in devising
specific risk scenarios. We have found that local source zones control the hazard for PGA and SA(T ≤ 1.0 s), although contribution from specific fault sources and long-distance north Algerian sources becomes significant
from SA(0.5 s) onwards. 相似文献
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