Probabilistic collocation and lagrangian sampling for advective tracer transport in randomly heterogeneous porous media     

Florian Müller  Patrick JennyDaniel W. Meyer 《Advances in water resources》2011,34(12):1527-1538

The Karhunen-Loeve (KL) decomposition and the polynomial chaos (PC) expansion are elegant and efficient tools for uncertainty propagation in porous media. Over recent years, KL/PC-based frameworks have successfully been applied in several contributions for the flow problem in the subsurface context. It was also shown, however, that the accurate solution of the transport problem with KL/PC techniques is more challenging. We propose a framework that utilizes KL/PC in combination with sparse Smolyak quadrature for the flow problem only. In a subsequent step, a Lagrangian sampling technique is used for transport. The flow field samples are calculated based on a PC expansion derived from the solutions at relatively few quadrature points. To increase the computational efficiency of the PC-based flow field sampling, a new reduction method is applied. For advection dominated transport scenarios, where a Lagrangian approach is applicable, the proposed PC/Monte Carlo method (PCMCM) is very efficient and avoids accuracy problems that arise when applying KL/PC techniques to both flow and transport. The applicability of PCMCM is demonstrated for transport simulations in multivariate Gaussian log-conductivity fields that are unconditional and conditional on conductivity measurements.  相似文献   

Modeling and Validating Long‐Term Dynamics of Diel Dissolved Oxygen with Particular Reference to pH in a Temperate Shallow Lake (Turkey)     

Nusret Karakaya  Fatih Evrendilek  Kerem Güngör 《洁净——土壤、空气、水》2011,39(11):966-971

Long‐term monitoring of changes in dissolved oxygen (DO) and pH is of great importance to quantifying aquatic ecosystem metabolism, particularly for lakes under the changing global environment. During 173 days, diel DO cycles were measured in situ along with the main driving variables of pH, wind speed (WS), and net solar radiation (Rn) in a temperate shallow lake. Best‐fit multiple non‐linear regression (MNLR) models of diel DO time series were built and validated on a monthly basis, with R² values ranging from 42.4% in September to 95.4% in November for validation. The strong relationship between diel DO and pH (r = 0.6) appeared to be related to the patterns of ecosystem productivity and respiration, and sensitivity of decomposing bacteria to changes in pH. pH‐driven lake metabolism appears to have significant implications for diel and seasonal lake metabolism in a changing global environment.  相似文献   

测井资料计算源岩有机碳含量模型对比及分析   总被引：1，自引：0，他引：1  

胡慧婷  卢双舫  刘超  王伟明  王民  李吉君  尚教辉 《沉积学报》2011,29(6):1199-1205

研究首先从理论分析入手,根据Δlog R模型在基线、有机碳含量背景值、叠合系数K、成熟度参数方面存在不足或不便推导出改进的Δlog R模型,针对改进Δlog R模型在测井参数选取方面的不足提出逐步回归模型;然后用具体实例对比三种模型应用效果,结合实例分析说明了改进的Δlog R模型优于Δlog R模型、逐步回归模型优于...  相似文献   

用知识管理带动勘察设计企业的信息化     

刘霁  王辉  谢卫 《中国勘察设计》2011,(3):72-75

本文遵循理论与实际相结合的指导思想,从知识管理的理论出发,围绕勘察设计企业的知识管理现状,分析勘察设计企业建设知识管理系统的必要性、阐述勘察设计企业知识管理的关键环节,提出建立勘察设计企业协同设计和知识管理为核心的综合管理信息系统方案。  相似文献   

兰州市滑坡地质灾害危险性研究          下载免费PDF全文

王云龙  文宝萍 《中国地质》2011,38(6):1593-1598

兰州是中国省会城市中地质灾害较为频发的地区之一,其地质灾害主要受地质、地形和人类活动等因素的影响。本文在分析兰州市区滑坡发育的控制因素和主要影响因素的基础上,以地理信息系统(GIS)为平台、采用专业数理统计软件SPSS中的逻辑回归模型(Binary Logistic)计算评价区内各单元格地质灾害的发生概率,通过GIS平台和SPSS软件之间数据格式的交换,利用GIS软件的空间分析功能,对兰州市滑坡灾害危险性进行了区划。研究结果与滑坡分布规律一致,对兰州市的地质灾害防治具有实际意义。  相似文献   

基于GA-SVR的渗透系数参数反演方法          下载免费PDF全文

陈海洋  膝彦国  王金生 《水文地质工程地质》2011,38(2):14-18

渗透系数参数反演的本质是优化问题求解,遗传算法是一种基于自然选择和群体遗传机理的新的全局优化求解方法,可以较好地用于求解诸如渗透系数参数反演等复杂非线性组合优化问题。基于结构风险最小化原理的支持向量机具有逼近复杂非线性系统、较强的学习泛化能力,可以用来计算渗透系数参数反演过程中的测点水头值。实验表明,基于遗传算法-支持向量回归机的地下水渗透系统参数反演拟合效果良好,能大大提升区间搜索效率,避免出现局部最优解,其参数识别精度符合实际应用要求。  相似文献   

含水层对地下水热泵承载力数值评价及其实用化:以北京平原区为例   总被引：1，自引：1，他引：0  

李世君  刘立才  郑凡东  江剑 《现代地质》2011,25(2):370-376

针对北京平原区的水文地质条件,运用地下热传递数值法评价了年内地下热量均衡、失衡两种状态下,各水文地质亚区单位面积含水层对地下水热泵的承载力,并利用多元线性回归方法阐明了承载力、抽灌井间距与含水层各参数之间的关系。研究表明:承载力仅与含水层厚度显著正相关,而抽灌井间距与含水层的渗透系数和厚度均显著正相关。研究结果为类似地区的地下水热泵定量规划提供了简捷的估算方法及参考依据。  相似文献   

Comparison of Two Sample Preparation Methods for X‐Ray Fluorescence Spectrometry in the Determination of Ni and Cr     

Surendra P. Verma  Rosalinda González‐Ramírez  Rodolfo Rodríguez‐Ríos 《Geostandards and Geoanalytical Research》2011,35(2):183-192

Pressed powder pellets and fused beads or glass disks are routinely used in X‐ray fluorescence spectrometry for the determination of major and trace elements, respectively, in geological materials. In order to evaluate the performance of these two sample preparation methods, we determined Ni and Cr concentrations of fourteen RMs from Japan, France and South Africa, and eighty‐five igneous and three sedimentary rock samples from Mexico in both powder pellets and glass beads. We also computed new values of statistical parameters for RMs from an outlier‐based multiple‐test method and compared them with the literature mean and confidence limit values. The results showed that the multiple‐test method provided more reliable central tendency and dispersion parameters for RMs than those obtained previously from the two or three standard deviation method, or from robust methods. The powder pellet and fused bead sample preparation methods provided consistent results for Ni and Cr at concentration levels > 50 μg g^?1 in this application; for lower concentration levels, however, these methods showed somewhat greater differences. For quantitative comparisons, both ordinary and weighted least‐squares linear regression models were used to show that the two sample preparation methods provided generally unbiased results.  相似文献   

吉林西部土壤有机碳含量与元素地球化学特征     

王冬艳  杨园园  李月芬  王孟  郭冬艳  靳克 《吉林大学学报(地球科学版)》2011,(Z1):333-338

针对土壤有机碳影响因素多且复杂而造成碳储量模拟模型中参数难以确定的问题,利用吉林西部167个典型土壤样点资料,通过统计分析对吉林西部表层土壤有机碳含量及元素地球化学进行了详细研究。结果表明:吉林西部土壤有机碳含量整体水平偏低,并存在着明显的区域分布特点,不同工作区的分异性不同;吉林西部土壤有机碳含量与Si含量、硅铝率、硅铝铁率和K含量之间存在着极显著的负相关,而与P、Al、Fe、Ca、Mg含量存在极显著的正相关;不同元素变异特征值可以解释土壤有机碳含量总变异的能力也不相同。通过研究土壤有机碳与元素含量的关系来定量研究土壤有机碳与土壤理化性质的关系是可行的,将二者量化关系与土壤有机碳储量模拟模型相结合,使得对土壤碳储量的认识更加科学。  相似文献   

Document based knowledge base engineering method for ship basic design     

Ying-Han Wu  Heiu-Jou Shaw 《Ocean Engineering》2011,38(13):1508-1521

We propose a basic ship design knowledge-model for information storage and retrieval using a knowledge-based engineering (KBE) system and develop a semantic inquiry function that allows users to use the retrieved information immediately. Our aim is to merge the repetitive access and calculating tasks and data such as the principal dimensions required during the basic ship design process into a single database, so that this information remains available for future construction projects. However, the concept of linking a design knowledge base and inference engine requires the combining of ship design information with the KBE system. This research enhances the flexibility, extension, and operation of the inference mechanism of the KBE design methodology through the establishment of a user interface, knowledge base, and inference engine. The design information is managed a document-based approach, which requires the conversion of the original documents into the XML (eXtensible Markup Language) format, and compiles rules for the basic design process. This system uses the KBE method attempts to reduce the double workload of design and modeling at the commencement of a new project with the document-generating integration work.  相似文献