首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 93 毫秒
1.
通过分析广西4个探空站资料,结合GGOS Atmosphere格网Tm数据,建立随高程增大的温度递减率模型。根据温度递减率模型分别采用反距离加权法、双线性插值法、新反距离加权法和新双线性插值法计算探空站Tm,通过分析插值误差建立广西非气象参数Tm模型,并与Bevis模型、中国东部模型、广西模型进行比较。结果表明,温度递减率模型的Tm插值精度相对其他3种模型有比较明显的提升,4种方法的平均绝对误差(MAE)和均方根误差(RMSE)在1~2 K之间;广西非气象参数Tm模型的插值精度得到进一步提高,百色站的MAE约为2 K,其余站点的MAE和RMSE均在1 K左右,能满足可降水量反演的精度要求。  相似文献   

2.
自然界中岩石内部均存在一定程度的损伤,损伤的持续演化过程对岩体的稳定性极为不利。为了研究岩石的损伤演化过程,将岩石分为未损伤部分、闭合裂隙部分与张开裂隙部分,采用统一强度理论与统计损伤理论分析岩石微元强度的分布,通过分析变形协调条件下各部分的应力-应变特征得到岩石的损伤本构模型与损伤演化模型,与巴东组紫红色泥岩三轴压缩试验结果对比验证后将模型应用于某反倾层状岩质边坡的破坏深度分析。分析结果表明:提出的损伤本构模型可以较好地模拟巴东组紫红色泥岩的三轴压缩应力-应变特性,提出的损伤演化模型可以较好地分析巴东组紫红色泥岩的损伤演化过程,且模型参数具有明确的物理意义;此外,根据基于损伤演化模型的反倾层状岩质边坡破坏深度修正模型计算得到的结果偏保守,用于岩土工程设计偏安全。   相似文献   

3.
为满足科研与生产的需要,基于有限元理论,推导了由现场位移观测值同时确定多种介质材料的物理力学参数的反分析模型。应用该模型进行的算例分析,表明了模型的正确性和有效性,且给出不同的初始值均能收敛到正确值。  相似文献   

4.
坐标拟合的双向解算与矩阵系数的生成   总被引:1,自引:0,他引:1  
在地理信息系统、机助制图等应用中,四参数与七参数拟合是坐标转换的重要方法。采取重合点坐标可获得正反算两套拟合参数,从而实现正反算求解。本文阐述了基于四参数与七参数这两种转换模型,通过重组矩阵模型,推求反算数学模型,采用一套拟合参数进行正反算的方法,并给出相应系数矩阵的自动生成程序和解算过程。  相似文献   

5.
近年来,随着遥感空间数据广泛应用于生态系统,推动了区域尺度生态遥感参数模型的发展。敏感性分析对识别模型关键参数,降低模型不确定性和完善模型具有重要作用。区域尺度的生态遥感参数模型,在进行模型参数敏感性分析时,由于涉及到空间数据的复杂运算,单机环境无法满足快速分析的要求。为了提高生态遥感参数模型空间敏感性分析效率,本文以青藏高原为研究区域,利用植被光合模型VPM(Vegetation Photosynthesis Model)和开源云计算平台Hadoop,设计和实现了基于Sobol′的生态遥感参数模型空间敏感性分析并行算法,并在实验室集群环境下进行算法分析,验证了算法的有效性和适用性。该算法的核心是利用MapReduce并行编程技术,对空间敏感性分析中的地图抽样和模型迭代过程进行任务分割,将分割后的子任务分配至不同的计算节点进行并行计算。实验表明,本文提出的并行策略,能有效缩短地图抽样和模型迭代计算时间,相比于单机算法,并行算法的运行速度提高了14倍左右。  相似文献   

6.
基于序列二次规划方法的高密度电阻率反演   总被引:3,自引:3,他引:0  
针对高密度电阻率成像法反演计算中存在的困难,探讨了基于序列二次规划(SQP)方法建立可行的电阻率反演算法的问题。在对三维点电源二维地电体电位场模型有限元法正演计算的基础上.建立了基于SQP方法的高密度电阻率成像法反演算法。根据勘测中测量电极间距的不同,提出按不同的电极间距分别建立优化模型进行参数优化。通过对模拟电阻率模型和实际观测资料的反演计算.表明该算法进行高密度电阻率反演是可行的,其具有对初始模型无特殊要求、收敛速度快的特点。这一反演算法可望在高密度电阻率成像的反演计算中得到应用。  相似文献   

7.
以下辽河平原为研究对象,在DRASTIC模型基础上,结合RS技术建立了DRASTICL(DRASTIC land use type)模型。利用ArcGIS的水文分析工具对DEM影像进行子流域划分与数据提取。通过对参数进行不确定性表征,对三角模糊参数设定不同α截集,在此基础上将随机参数和模糊参数进行蒙特卡罗模拟。将不同α截集下模拟结果代入模糊模式识别模型,根据累积分布规律,选取不同百分位,从而得出不同α截集与不同百分位地下水脆弱性取值。结合ArcGIS数据可视化表达,得出不同α截集下下辽河平原浅层地下水脆弱性分布图,以此辨析下辽河平原浅层地下水不确定性与脆弱性程度。最后运用灵敏度分析辨别各参数对模拟结果的实际贡献程度。结果表明:(1)模糊模式识别模型用非线性的形式充分反映参数连续性变化对模拟结果产生的影响。(2)加入土地利用类型参数,结果更能反映人类活动影响下地下水脆弱程度。(3)不同α水平、不同百分位、与不同灵敏度系数3个层次的分析有效处理了参数不确定性问题,为制定相关政策提供更加准确的参考依据,对今后本地区的地下水环境开发利用和保护具有重要意义。  相似文献   

8.
分析了GPS相对定位中对流层折射的特点,概述了目前所采用的几种确定性参数对流层折射估计和随机过程参数对流层折射估计方法。根据实测数据处理结果,分析比较了几种确定性模型和随机过程模型对GPS相对定位精度的改善作用。结果表明:对流层折射的多参数确定性模型和随机参数模型对基线分量的重复性,特别是高程分量的重复性有明显改善;在大多数情况下,尤以随机参数模型为佳,其垂直分量的重复性精度较单参数模型可提高一倍左右。  相似文献   

9.
探讨了一类推广的Leslie-Gower型捕食-被捕食模型的动力学性质。以HollingII型功能反应和推广的Leslie-Gower模式为基础建立了无时滞和有时滞的捕食-被捕食种间作用模型;分析了无时滞模型共生平衡点的稳定性和Hopf分支,得到了共生平衡点的稳定性条件,找到了使系统发生Hopf分支的参数临界值,建立了系统存在稳定极限环的条件;分析了时滞模型系统共生平衡点的渐近稳定性以及孕育时滞参数值变化对模型系统共生平衡点稳定性的影响,找到了时滞模型系统发生Hopf分支的参数临界值,证明了当时滞参数在临界值附近变化时,系统也将发生Hopf分支。  相似文献   

10.
对折射率反导引效应对半导体激光器阈值、横模、纵摸、调制等特性的影响作了理论上的分析和总结,并在考虑不同参数的情况下对由此引起的频率啁啾作了数值计算,计算表明,折射率反导引效应对半导体激光器小信号调制频率啁啾的影响程度随器件参数的不同而不同。  相似文献   

11.
Using a combination of close-range photogrammetry and three-dimensional(3-D) limit equilibrium theory, a determination method for the shear strength parameters of rock-soil mixture is presented. A close-range photogrammetry method is used for measurement of the 3-D terrain of the experimental target. Auto CAD Lisp and EXCEL VBA are used to perform 3-D limit equilibrium analysis of the stability of sliding mass and perform backanalysis of shear strength parameters. The presented method was used to determine the shear strength parameters of rock-soil mixtures at the Liyuan Hydropower Station. The 3-D terrain of sliding surface could be measured notably well using of closerange photogrammetry. The computed results reveal that the cohesion and friction angle of rock-soil mixtures were 3.15 k Pa and 29.88o for test A, respectively, and 4.43 k Pa and 28.30o for test B, respectively, within the range of shear strength parameters, as determined by field and laboratory tests. The computation of shear strength parameters is influenced by the mesh grid number, especially the cohesion of the rock-soil mixture. The application of close-range photogrammetry can reduce the siteworks and improve the computational efficiency and accuracy.  相似文献   

12.
如何使用少量的地形特征复原地形地貌一直为地学领域的难题。本文使用开源数据集提取地形特征要素,使用地形特征要素作为约束条件构建了用于生成DEM的条件生成对抗网络(Conditional Generative Adversarial Networks, CGAN),设计了基于开源DEM、开源DEM与遥感影像组合、以及5m高精度DEM提取地形特征要素生成DEM的对比实验,并对结果进行视觉效果、相关性分析以及地形因子的对比与评价。结果表明:(1)在视觉效果上,3种不同方式生成的DEM在视觉效果上均十分逼近原始5 m DEM,都远好于传统插值方法生成DEM,基于开源12.5m DEM提取要素和1m遥感影像的重建效果最接近于原始5 m DEM;(2)在相关性上,三种不同方式生成的DEM与原始5m DEM相关性均能达到0.75以上,组合开源数据提取要素重建DEM与原始5 m DEM相关性可达到0.85以上;(3)在地形因子方面,基于开源12.5 m DEM和1 m遥感影像提取要素重建DEM的坡度和坡向的分布趋势与原始5 m DEM最为一致。本文为高精度DEM建模提供了新的思路,在高精度DEM难以获取...  相似文献   

13.
?????????1999??????GPS?????????д??????????GPS?????????????????????媲λ?????????????????????????????????????????????????????о???????????????壬?о????????????????????С????????????????????????????????????????????????????????????????????????1 mm/a?????κ???α????????????????????????40 km??30 km???????????????????????????????????????1 mm/a??????????????30 km????????????????????????????????1 mm/a?????????????????40 km??  相似文献   

14.
Based on the electrical properties and structural-tectonic principles, several geo-electric models have been established for the hydrogeologic provinces in Primorski Krai. They are mainly two-layered near-horizontally-layered model with a high-resistivity underlying horizon, multiple-layered model with subhorizontal interfaces, model with an inclined interface and a pinching bed, and model with a local extended inclusion. And these models can provide good basin for searching for ground water in the region.  相似文献   

15.
A framework is proposed to characterize and forecast the displacement trends of slow-moving landslides, defined as the reactivation stage of phenomena in rocks or fine-grained soils, with movements localized along one or several existing shear surfaces. The framework is developed based on a thorough analysis of the scientific literature and with reference to significant reported case studies for which a consistent dataset of continuous displacement measurements is available. Three distinct trends of movement are defined to characterize the kinematic behavior of the active stages of slow-moving landslides in a velocity-time plot: a linear trend-type I, which is appropriate for stationary phenomena; a convex shaped trend-type II, which is associated with rapid increases in pore water pressure due to rainfall, followed by a slow decrease in the groundwater level with time; and a concave shaped trend-type III, which denotes a non-stationary process related to the presence of new boundary conditions such as those associated with the development of a newly formed local slip surface that connects with the main existing slip surface. Within the proposed framework, a model is developed to forecast future displacements for active stages of trend-type II based on displacement measurements at the beginning of the stage. The proposed model is validated by application to two case studies.  相似文献   

16.
罗洪,邓先瑞THEVERTICALDISTRIBUTIONOFAGROTOPOCLIMATICRESOURCESINTHEWARMSECTORSOFTHETHREEGORGESAREAOFTHECHANGJIANGRIVER¥DengXianrui;...  相似文献   

17.
INTRODUCTIONThegenusPraebebaliawasestablishedbyRathbun ,1 91 1 .Itscarapaceisbroaderthanlongaslongasbroad ,orslightlylongerthanbroad ;theposteriorborderisusuallyarmedwithaspineortu bercleoneachside ,thehepaticandintestinalregionsaredistinctlyelevated ;thechel…  相似文献   

18.
????Z???ζ????????????????ο?????FLAC??3D??????о????????????????????????9??????????????????????й???????????????о?????????????λ???????м????????????????????м??????????????????????????????Щ??????????й???????Щ???????????й??????????????????????????д??????????????????????????  相似文献   

19.
The existing models of population distribution often focus on the region with a single city or even multiple centers, and lack the detailed explorations of the common and special type of urbanization areas with two centers. Taking Beijing-Tianjin region of China, which is a distinct dual-nuclei metropolitan area in the world, as an example and choosing Landsat-5 TM image in 2005, population, etc. as the data, this paper devotes to comprehending and illustrating a model of Cassini growth of population between the two metropolitan cities through the research of spatial population distribution pattern, aided with RS and GIS techniques. Main technical processes include Kriging interpolation of the population data and character simulation of the Cassini ovals. According to the calculation of a/b, a key characteristic index of Cassini growth model, the spatial structures of population distribution were given. When a/b<1, it is a curve with two separated loops with a population density more than 3000 persons/km2. When a/b=1, it is a lemniscate curve with a population density about 3000 persons/km2. When 1<a/b√2, it is a dog-bone shaped concave curve with a population density between 500–3000 persons/km2. When a/b=√2, it is an oblate curve with a population density about 500 persons/km2. When a/b>√2, there is an oval-shaped convex curve with a population density less than 500 persons/km2. The results show that owing to the combined action and influence of the regional dual-nuclei, the population distribution of Beijing-Tianjin region is in accord with Cassini model significantly. There-fore, there is Cassini growth of population between the two metropolitan cities in Beijing-Tianjin region. In addition, the process of Cassini growth has extraordinarily instructive significance for judging the development stages of the dual-nuclei metropolitan areas. Foundation item: Under the auspices of National High-Tech Research and Development Program of China (863 Program) (No. 2007AA12Z235), National Natural Science Foundation of China (No. 40471058)  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号