Optimization with the Gradual Deformation Method   总被引：1，自引：0，他引：1  

Mickaële Le Ravalec-Dupin  Benoît Ntinger 《Mathematical Geology》2002,34(2):125-142

Building reservoir models consistent with production data and prior geological knowledge is usually carried out through the minimization of an objective function. Such optimization problems are nonlinear and may be difficult to solve because they tend to be ill-posed and to involve many parameters. The gradual deformation technique was introduced recently to simplify these problems. Its main feature is the preservation of the spatial structure: perturbed realizations exhibit the same spatial variability as the starting ones. It is shown that optimizations based on gradual deformation converge exponentially to the global minimum, at least for linear problems. In addition, it appears that combining the gradual deformation parameterization with optimizations may remove step by step the structure preservation capability of the gradual deformation method. This bias is negligible when deformation is restricted to a few realization chains, but grows increasingly when the chain number tends to infinity. As in practice, optimization of reservoir models is limited to a small number of iterations with respect to the number of gridblocks, the spatial variability is preserved. Last, the optimization processes are implemented on the basis of the Levenberg–Marquardt method. Although the objective functions, written in terms of Gaussian white noises, are reduced to the data mismatch term, the conditional realization space can be properly sampled.  相似文献   

城市人口GIS中数据的不确定性研究   总被引：8，自引：0，他引：8  

柳宗伟  王新洲  陈顺清 《武汉大学学报(信息科学版)》2002,27(6):627-631

针对系统数据源、数据模型的不确定性以及分析过程中引入的不确定性等问题进行了系统的研究，并归纳了各种不确定性的影响模型，进而提出了一套人口GIS数据优化建模以及分析过程中人口密度中心建模的思想和实用方法，用于克服人口GIS中数据的不确定性的影响。  相似文献   

Land Use Structure Optimization Under Systematic Framework     

LIU Yanfang HUANG Liangprofessor  School of Resource  Environment Science  Wuhan University  Luoyu Road  Wuhan  China. 《地球空间信息科学学报》2002,5(3):46-52

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Optimization of Land Use Structure Based on Ecological GREEN Equivalent   总被引：1，自引：0，他引：1  

LIU  Yanfnag  MING  Dongping 《地球空间信息科学学报》2002,5(4):60-67

Optimization of land use structure consists of economic and social and ecological optimization.Applying the minds of system engineering and principles of ecology,this paper presents such thoughts:the optimal forest-coverage rate calculated according to the reality of a district is set as main standard of ecological rationality in the district;through considering the value of ecosystem services of the land with GREEN equivalent(mainly cultivated land and grassland)and based on the rule GREEN equivalent,this paper introduces the area conversion between woodland and cultivated land ,also between woodland and grassland;this paper establishes a multi-dimension controlling model of optimization of land use structure,In addition,a multiobjective linear programming model for optimization of land use structure is designed.In the end,this paper tests and verifies this theory of ecological optimization,taking Qionghai city in Hainan Province as an example.  相似文献   

全球地壳运动的背景场及其研究进展   总被引：1，自引：0，他引：1  

金双根  朱文耀 《地球科学进展》2002,17(5):782-786

全球地壳运动是在全球地壳运动背景场中发生的，其背景场的运动参数是表征地壳运动的最基本特征。由于现今板块运动模型ITRF序列均忽略板块边界部分，并且板块以NUVEL1A模型来划分，由此建立的全球板块运动模型不能作为一个严格的全球地壳运动背景场。利用区域速度场和ITRF2000速度场建立一个包括非刚体的板块边界区域和刚体板块的全球地壳运动模型，其板块总角动量ΙLΙ＝0．131°/Ma，即不为零，存在整体旋转，由此建立无整体旋转（NNR）模型，并评述其研究进展。  相似文献   

重庆秀山寒武系锶同位素演化曲线及全球对比   总被引：15，自引：0，他引：15  

黄思静  石和等 《地质论评》2002,48(5):509-516

本文评述了国际上已有的寒武纪海相碳酸盐的锶同位素演化曲线，公布了重庆秀山寒武系海相碳酸盐的锶同位素分析结果，尽管对样品进行了成岩蚀变检测和必要的筛选，但样品仍可能不同程度地经历了成岩蚀变，锶同位素组成与地层厚度投点图显得较为离散，笔者主要利用87Sr/86Sr比值较低的样品建立的寒武纪海水的锶同位素演化曲线在长期旋回上与国际上已公布的同时代锶同位素演化曲线仍具有较好相似性和可比性，说明全球事件是海水锶同位素组成的主要控制因素，海水的87Sr/86Sr比值在盆内对比，盆间对比，以及全球对比中都具有潜在价值。根据锶同位素地层学的基本原理，笔者尝试确定了重庆秀山寒武纪剖面一些关键点的年龄，累积厚度1340m处的年龄为503－509Ma，累积厚度1950m处的年龄为496－498Ma，这对秀山寒武纪剖面下，中寒武统和中、上寒武统界线的确定具有参考价值。  相似文献   

Obtaining refined first‐order predictive models of linear structural systems     

Hilmi Lu  Raimondo Betti  Richard W. Longman 《地震工程与结构动力学》2002,31(7):1413-1440

This study presents an effective method for identifying predictive models and the underlying modal parameters of linear structural systems using only measured output and excitation time histories obtained from dynamic testing. The system under examination is modelled as a first‐order multi‐input multi‐output time‐invariant system, and the structural model is realized using the Eigensystem Realization Algorithm together with the Observer/Kalman filter IDentification algorithm. The identified state‐space model is further refined using a non‐linear optimization technique based on sequential quadratic programming. The numerical examples show that the developed methodology performs very well even in the presence of inadequate instrumentation and measurement noise, and that the methodology is highly capable of creating realistic predictive models of structural systems, as well as estimating their underlying modal parameters. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

“数字油田”的理论与实践     

何生厚  韦中亚 《地理与地理信息科学》2002,18(2):5-7

石油天然气工业是我国的支柱能源产业 ,具有行业涉及专业多、建设投资大、研究主体是隐藏在地下巨大的流动矿资源、数据是第一财富等特点。石油天然气工业的信息化意义重大 ,该文结合作者的“数字油田”实践 ,给出了“数字油田”的理论技术、设计方法和实现路线  相似文献   

Reviews     

《The Geographical journal》2002,168(4):380-382

Books reviewed:
Bjørn Lomborg, The Skeptical Environmentalist: Measuring the real state of the world
B. Dalal–Clayton and D. Dent, Knowledge of the Land: Land resources information and its use in rural development
Krishna B. Ghimrie, The Native Tourist: Mass tourism within developing countries  相似文献   

全球生产网络(GPN)的理论问题和中国实践启示     

陈蕊  刘逸 《地理研究》2021,40(12):3259-3271

全球生产网络理论（GPN）是关系经济地理学派的核心理论成果,但当前国内外研究对其发展脉络和理论内涵的认识存在模糊之处,在应用方面也存在一些误区。因此,本文从GPN与全球价值链（GVC）理论互动的视角出发,回顾GVC和GPN的重要发展阶段及对彼此的影响,针对常见的对GPN理解和应用的误区展开解释与辨析,主要得到3个结论。第一,GPN理论的研究目的已从解释“价值生产”凝练为解释“区域发展的不均衡”,更贴近经济地理学的基本研究范式。第二,GPN与GVC正在从分歧走向融合,共同致力于捕捉与解释全球化动态。第三,并非所有跨国公司研究或生产网络研究都属于GPN研究,GPN专指研究跨国公司与主要相关者基于生产所形成的网络动态,不适用于以国家为单位的研究,也不着力于揭示企业内部经营管理动态。本文继而指出中国经验既需要GPN理论加以探析、也有助于丰富GPN理论,精准理解GPN尤其对中国当前推行双循环战略有重要应用价值。本文强调,GPN作为中观理论框架,有效解释了全球经济中区域发展的多尺度动态,在全球化出现逆流的新形势下,对中国全球化实践,特别是国际国内双循环发展有着鲜明的研究意义。  相似文献