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51.
介绍了计算样本相似性方法在油气预测中的应用的基本原理和技术。提出了利用参数的显著性进行参数优化和加权的方法。该方法简单、实用,并在塔北某区的应用取得了满意结果。由此证明了该方法的有效性及在综合信息预测工作中进行参数优化和加权工作的重要性。 相似文献
52.
A. Douaik M. van Meirvenne T. Tóth M. Serre 《Stochastic Environmental Research and Risk Assessment (SERRA)》2004,18(4):219-227
The mapping of saline soils is the first task before any reclamation effort. Reclamation is based on the knowledge of soil salinity in space and how it evolves with time. Soil salinity is traditionally determined by soil sampling and laboratory analysis. Recently, it became possible to complement these hard data with soft secondary data made available using field sensors like electrode probes. In this study, we had two data sets. The first includes measurements of field salinity (ECa) at 413 locations and 19 time instants. The second, which is a subset of the first (13 to 20 locations), contains, in addition to ECa, salinity determined in the laboratory (EC2.5). Based on a procedure of cross-validation, we compared the prediction performance in the space-time domain of 3 methods: kriging using either only hard data (HK) or hard and mid interval soft data (HMIK), and Bayesian maximum entropy (BME) using probabilistic soft data. We found that BME was less biased, more accurate and giving estimates, which were better correlated with the observed values than the two kriging techniques. In addition, BME allowed one to delineate with better detail saline from non-saline areas. 相似文献
53.
针对当今的数值预报模式中存在若干与热力学第二定律不符的问题,本文着重讨论了将该定律引入数值预报模式的必要性,并通过已引入和未引入第二定律的中尺度数值模式MM5V3两者之间的对比试验来验证在数值预报模式中引进热力学第二定律的可行性。 相似文献
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56.
The shear viscosities and 1 bar heat capacities of glasses and melts along the 67mol% silica isopleth in the system SiO2-Al2O3-Na2O-TiO2 have been determined in the temperature ranges 780-1140 K and 305-1090 K respectively. Anomalous behaviour of both these properties is observed for compositions rich in TiO2 and/or Al2O3, an observation attributed to liquid-liquid phase separation followed by anatase crystallization. For samples which do not show anomalous behaviour, it is found that the partial molar heat capacity of the TiO2 component previously determined in Al-free compositions reproduces our heat capacities to within 1.3%. Viscosity data show that addition of TiO2 tends to increase viscosity and melt fragility at constant temperature. Furthermore, heat capacity and viscosity data may be combined within the framework of the Adam-Gibbs theory to extract values of the configurational entropy of the liquids and qualitative estimates of the variation of the average energy barrier to viscous flow. Configurational entropy at 900K is inferred to decrease upon addition of TiO2, in contrast to previous results from Al-free systems. The compositional limit separating normal from anomalous behaviour, as well as the data for homogenous melts have been used to constrain the structural role of Ti in these samples. Our data are consistent with a majority of Ti in five-fold coordination associated with a titanyl bond, in agreement with previous spectroscopic studies. Furthermore, we find no evidence for a Ti-Al interaction in our samples, and we are led to the conclusion that Al and Ti are incompletely mixed, a hypothesis consistent with the observed reduction of configurational entropy upon addition of TiO2, suggesting an important role of medium range order in controlling the variations in thermodynamic properties. 相似文献
57.
基于灰关联分析的GPS高程拟合加权平均函数模型权函数优选 总被引:6,自引:0,他引:6
基于灰色系统理论的灰关联分析方法,提出了权函数的优选方法,实例分析表明其具有较好的实用价值. 相似文献
58.
Jonathan D. Phillips 《The Professional geographer》2005,57(1):83-93
Spatial systems are typically characterized by multiple controlling factors and processes operating at different spatial and temporal scales (multiple scale causality [MSC]). An entropy decomposition‐based approach to MSC is presented here in two contexts. First, given maps or distributions of an observed phenomenon at two or more scales, the contribution at more local or global (relative to the primary scale of observation) controls to the observed entropy can be estimated. Second, a theoretical treatment of the entropy decomposition equations shows that as the range of scale is increased by broadening or narrowing resolutions or by incorporating more controls, the influence of larger or smaller‐scale influences not only changes, but may change qualitatively, e.g., in terms of having positive (entropy‐increasing) or negative (information‐increasing) effects. Such qualitative causal shifts have implications for efforts to use any single causal explanation across the molecular to planetary spatial and instantaneous to geological range of scales relevant to physical geography. The entropy decomposition method is illustrated with an application to soil landscapes in the Ouachita Mountains, Arkansas. 相似文献
59.
The objective of this study was to estimate genetic parameters of body width(BW)to body length(BL)ratio(BW/BL)and of body weight traits(BWT)in turbot,and to elucidate the genetic mechanism of the two traits during ontogeny by dynamic genetic analysis.From 3 to 27 months,BW,BL and BWT of each communally stocked fish were measured every 3 months.The BW/BL ratio was measured at different sampling ages.A twotrait animal model was used for genetic evaluation of traits.The results showed that the heritability values of BW/BL ratio ranged from 0.2168 to 0.3148,corresponding to moderate heritability.The BWT heritability values ranged from 0.2702 to 0.3479 corresponding to moderate heritability.The heritability of BW/BL ratio was lower than that of BWT,except at 3 months of age.Genetic correlation between BW/BL ratio and BWT decreased throughout the measurement period.Genetic correlations were higher than the phenotypic correlations.The current results for estimating genetic parameters demonstrate that the BW/BL ratio could be used as a phenotypic marker of fast-growing turbot,and the BW/BL ratio and BWT could be improved simultaneously through selective breeding. 相似文献
60.
中国旅游城市生态安全系统评估与类型划分研究 ——基于节点权重约束网络DEA模型 总被引:2,自引:2,他引:0
采用 DPSIR概念模型作为旅游生态安全系统的基本形态,引入网络 DEA模型测度系统运行效率,从“投入-产出”的研究视角探究旅游生态安全系统内部作用机理。采用结构方程模型对网络 DEA模型的结构及权重加以限制,构建具有节点权重约束的网络 DEA评价模型,对主要旅游城市生态安全系统实例进行实证研究。研究结果认为:将生态安全系统分为自然运行阶段、管理反馈阶段2阶段进行效率评价,加权综合得出各旅游城市生态安全系统的综合评价值,以此为依据将样本城市划分为按系统效率的评价结果将其分划为绿色发展型、稳步发展型、高效发展型、双向提升型和管理能力缺失型,针对各类型旅游城生态安全系统特点提出改善其生态安全系统状况的建议。 相似文献