遗传算法在边坡数值计算中的应用   总被引：4，自引：0，他引：4  

安关峰  殷坤龙等 《地球科学》2002,27(2):177-180

改进了进化方向的遗传算法与有限元数值法，结合并研制了相应的软件。应用该软件对多类型岩土边坡进行弹性模量、内聚力、内摩擦角等参数反演分析，显示误差很小，收敛速度也很快，这说明改进进化方向遗传算法这种新型的优化算法在多类型岩土参数优化估计中具有独特的优势。  相似文献   

Combination of Dependent Realizations Within the Gradual Deformation Method     

Lin Y. Hu 《Mathematical Geology》2002,34(8):953-963

Gradual deformation is a parameterization method that reduces considerably the unknown parameter space of stochastic models. This method can be used in an iterative optimization procedure for constraining stochastic simulations to data that are complex, nonanalytical functions of the simulated variables. This method is based on the fact that linear combinations of multi-Gaussian random functions remain multi-Gaussian random functions. During the past few years, we developed the gradual deformation method by combining independent realizations. This paper investigates another alternative: the combination of dependent realizations. One of our motivations for combining dependent realizations was to improve the numerical stability of the gradual deformation method. Because of limitations both in the size of simulation grids and in the precision of simulation algorithms, numerical realizations of a stochastic model are never perfectly independent. It was shown that the accumulation of very small dependence between realizations might result in significant structural drift from the initial stochastic model. From the combination of random functions whose covariance and cross-covariance are proportional to each other, we derived a new formulation of the gradual deformation method that can explicitly take into account the numerical dependence between realizations. This new formulation allows us to reduce the structural deterioration during the iterative optimization. The problem of combining dependent realizations also arises when deforming conditional realizations of a stochastic model. As opposed to the combination of independent realizations, combining conditional realizations avoids the additional conditioning step during the optimization process. However, this procedure is limited to global deformations with fixed structural parameters.  相似文献   

岩浆混合作用——来自甘肃北山的野外证据   总被引：4，自引：0，他引：4       下载免费PDF全文

梁明宏  周兴安  龚全胜  李海林 《甘肃地质》2002,11(1):44-49

在 1∶2 5万马鬃山幅区调填图和方法研究工作中 ,通过观察到的一些与岩浆混合模式相关的现象 ,指出暗色微粒镁铁质包体是岩浆混合作用的有利证据 ,讨论了与花岗岩侵入体相关的镁铁质小岩体混合成因的可能性 ,认为岩浆混合作用在造山带岩浆活动中是一种极为普遍的现象。  相似文献   

Application of genetic BP network to discriminating earthquakes and explosions     

边银菊 《地震学报(英文版)》2002,15(5):540-549

Introduction Artificial Neural Network (ANN) is an important branch of artificial intelligence. It is proposed on the foundation of the study on modern neural science, is a man-made network that can implement some functions based on the mans comprehensive understanding for cerebral neural network (HAN, WANG, 1997). ANN is a mathematical model of simplified human brain neural network and is used to simulate the structures and functions of human brain neural network. ANN is a complex netw…  相似文献   

三维地震数据离散光滑插值的共轭梯度法   总被引：5，自引：3，他引：5       下载免费PDF全文

李冰  刘洪  李幼铭 《地球物理学报》2002,45(5):691-699

针对三维地震数据插值,提出采用Laplacian算子进行光滑约束的插值方法,并借鉴Mallet研究的离散光滑插值思路,采用预条件共轭梯度法,直接生成网格节点上的值,从而回避寻求满足插值方程的函数. 为了实现其中Laplacian算子的快速求逆,文中引入Claerbout螺旋坐标系谱因式分解理论. 在螺旋坐标系下,Laplacian算子的表示矩阵具有Toeplitz结构,其快速求逆可由谱法LU分解实现. 基于二维离散光滑插值,文中还给出共轭梯度法与NMO相结合的沿时间切片逐层处理的离散光滑插值流程. 最后,应用该方法对模型数据和实际三维地震数据进行了处理.  相似文献   

Melting of β-quartz up to 2.0 GPa and thermodynamic optimization of the silica liquidus up to 6.0 GPa     

Pierre Hudon  In-Ho Jung  Don R. Baker 《Physics of the Earth and Planetary Interiors》2002,130(3-4):159-174

Melting relations of β-quartz were experimentally determined at 1.0 GPa (1900±20 °C), 1.5 GPa (2033±20 °C), and 2.0 GPa (2145±20 °C) using a new high-pressure assembly in a piston–cylinder apparatus and substantial differences were found with data previously reported. The new melting data of β-quartz were combined and optimized with all available thermodynamic, volumetric, and phase equilibria data for β-cristobalite, β-quartz and coesite to produce a P–T liquidus diagram for silica valid up to 6.0 GPa. Using the new optimized thermodynamic parameters, the invariant point β-cristobalite+β-quartz+liquid and β-quartz+coesite+liquid were determined to lie at 1687±17 °C and 0.457 GPa, and 2425±25 °C and 5.00 GPa, respectively.  相似文献   

海洋平台结构振动的AMD主动控制参数优化分析   总被引：5，自引：0，他引：5  

张春巍  欧进萍 《地震工程与工程振动》2002,22(4):151-156

本文针对海洋平台结构的冰激振动和地震反应控制问题，提出了采用AMD主动控制的控制策略，结合JZ20－2MUQ平台结构进行了AMD控制系统的硬参数和软参数的优化分析，并就相应于最优参数下的AMD控制海洋平台结构冰激振动和地震反应的几种代表性工况进行了时程分析，得到了一些定性和定量的结论，为实际工程的控制设计提供了基础。本文提出的AMD主动控制方法对类似的海洋平台结构的控制问题也有参考价值。  相似文献   

Seismic structural control using semi-active tuned mass dampers   总被引：8，自引：1，他引：8  

杨润林  周锡元  刘锡荟 《地震工程与工程振动(英文版)》2002,1(1):111-118

This paper focuses on how to determine the instantaneous damping of the semi-active tuned mass damper (SATMD) with continuously variable damping. An off-and-towards-equilibrium (OTE) algorithm is employed to examine the control performance of the structure/SATMD system by considering the damping as an assumptive control action. The damping modification of the SATMD is carried out according to the proposed OTE algorithm, which is formulated based on analysis of the structural movement under external excitations, and the measured responses of the structure at every time instant. As examples two numerical simulations of a five-storey and a ten-storey shear structures with a SATMD on the roof are conducted. The effectiveness on vibration reduction of MDOF systems subjected to seismic excitations is discussed. Analysis results show that the behavior of the structure with a SATMD is significantly improved and the feasibility of applying the OTE algorithm to the structural control design of SATMD is also verified.  相似文献   

投影寻踪门限回归模型在年径流预测中的应用   总被引：9，自引：4，他引：9  

金菊良  魏一鸣  丁晶 《地理科学》2002,22(2):171-175

为预测年径流这类同维复杂动力系统，提出了投影寻踪门限回归（PPTR）模型。构造了新的投影指标函数，用门限回归（TR）模型描述投影值与预测对象间的非线性关系，并用实码加速遗传算法优化投影指标指数函数和TR模型参数。实例的计算结果表明，用PPTR模型预测年径流是可行而有效的。PPRT模型简便、适用性强，克服了目前投影寻踪方法计算量大、编程实现困难的缺点，有利投影寻踪方法的推广应用，为解决高维非线性复杂预测问题提供了新途径。  相似文献   

Non-smooth gravity problem with total variation penalization functional   总被引：1，自引：0，他引：1  

H. Bertete-Aguirre  E. Cherkaev  M. Oristaglio 《Geophysical Journal International》2002,149(2):499-507

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