Numerical Analysis of Space–Time Finite Element Formulations for Miscible Displacements     

Rigoberto G. Sanabria Castro  Sandra M. C. Malta  Abimael F. D. Loula  Luiz Landau 《Computational Geosciences》2002,5(4):301-330

A finite element formulation is proposed to approximate a nonlinear system of partial differential equations, composed by an elliptic subsystem for the pressure–velocity and a transport equation (convection–diffusion) for the concentration, which models the incompressible miscible displacement of one fluid by another in a rigid porous media. The pressure is approximated by the classical Galerkin method and the velocity is calculated by a post-processing technique. Then, the concentration is obtained by a Galerkin/least-squares space–time (GLS/ST) finite element method. A numerical analysis is developed for the concentration approximation. Then, stability, convergence and numerical results are presented confirming the a priori error estimates.  相似文献   

Simulation of artificial random field considering the temporal-spatial variation     

倪永军  朱晞 《地震学报(英文版)》2002,15(4):425-430

Introduction For the seismic design of special structures such as nuclear power station, marine platform, long-span bridge and dam, generally the time-history response analysis of the structure under seismic excitation is imperative, which was coded in most seismic design codes. The earthquake records suitable for the seismic situation and site condition are necessary to be used as the seismic input in the dynamic analysis of structures. As a result of the limited observational condition of st…  相似文献   

桥梁限位器抗震设计方法研究   总被引：4，自引：0，他引：4  

戴福洪  翟桐 《地震工程与工程振动》2002,22(2):73-79

本文建立了两跨简支梁桥和五跨多跨刚架桥两结构模型，针对限位器的种类、刚度、强度、安装位置，输入地震动等进行了大量工况下的数值模拟研究。研究表明限位器与柱（框架）的刚度比在0.5-2之间较优。将现有的限位器设计方法应用于两算例结构，对现有限位器设计方法进行了比较研究。  相似文献   

高层钢框架-支撑结构二阶非线性随机地震响应分析   总被引：1，自引：0，他引：1  

陈兰  汤海波  梁启智 《地震工程与工程振动》2002,22(3):170-174

针对常用的高层钢框架－支撑结构，考虑材料非线性和几何非线性，建立了框架部分、支撑部分的二阶动力分析模型。用等效线性方法对结构进行非线性随机地震响应分析，结合工程算例，论述不同场地土、不同层数、不同支撑情况下，二阶效应对结构地震响应统计量的影响。  相似文献   

依据剖面资料求解断层的水平位移     

安晓文  李世成  周瑞琦  俞维贤  陈宇军 《地震研究》2002,25(4):369-373

提出依据开挖剖面中的楔形体在受到断层作用时其厚度的变化量求解断层水平位移的方法。分析表明断层水平位移量S与楔形体在断层两侧厚度变化量Δh满足关系式S＝Δh/ρsinβ。式中ρ为楔形体在断层走向上的尖灭系数，β为断层的倾角，该关系式不仅能满足纯走滑运动的断层，而且也满足一般斜滑断层，同时提出了在剖面上判断断层水平运动性质的方法。  相似文献   

Recent developments in seismically isolated buildings in Japan     

Shin Okamoto  Nagahide Kani  Masahiko Higashino  Norihide Koshika  Masayuki Kimizuka  Mitsumasa Midorikawa  Masanori Iiba 《地震工程与工程振动(英文版)》2002,1(2):213-225

The Building Standard Law of Japan and related Enforcement Order and Notifications have been substantially revised since the year 2000 to introduce a performance-based regulatory and deregulation system for building control systems. Up to then, time-history analyses were mandatory for isolated buildings and had to be specially approved by the Minster of the Ministry of Construction (MOC). Simplified design procedures based on the equivalent linear method for seismically isolated buildings have been issued as “Notification 2009 — Structural calculation procedure for buildings with seismic isolation” from MOC, and are now integrated into the Ministry of Land, Infrastructure, and Transportation (MLIT). Along with Notification 2009, “Notification 1446 of year 2000 — Standard for specifications and test methods for seismic isolation devices” was also issued. Buildings with heights equal to or less than 60m and that are designed according to these Notifications, including base isolated buildings, only need approval from local building officials, and no longer require the special approval of the Minister of MLIT. This paper summarizes: 1) some statistics related to buildings with seismic isolation completed up to the end of 2001; 2) simplified design procedures required by Notification 2009 of year 2000; and 3) performance of seismic isolation devices required by Notification 1446 of year 2000.  相似文献   

位移监测在滑坡时空运动研究中的应用   总被引：5，自引：0，他引：5  

靳晓光  王兰生  李晓红 《山地学报》2002,20(5):632-635

滑坡时空运动特征是滑坡地质体在内因和外因共同作用下，自一种状态向另一种状态转化的地质过程。滑坡位移监测是研究滑坡变形影响因素、动态规律及预测预报的主要途径，特别是滑坡深部位移监测，又为研究滑坡体的时空运动过程提供了重要信息。本文结合几个滑坡的深部位移监测实践，综合分析位移监测信息，研究滑坡体的时空运动特征及发展趋势，为滑坡时空运动系统研究及稳定性预测提供依据。  相似文献   

Geographies of Displacement: The Karenni and The Shan Across The Myanmar-Thailand Border   总被引：1，自引：0，他引：1  

Carl Grundy-Warr  & Elaine Wong Siew Yin 《Singapore journal of tropical geography》2002,23(1):93-122

First, central to our analysis is the argument that human movement within and across borders fundamentally challenges the view of geopolitics based upon fixed territorial states, inter-state relations, national identities and citizenship; indeed the whole idea of "national geographic". Using the examples of the Karen and Shan peoples, we explore the processes and patterns of forced relocation, displacement and migration in the border regions of Myanmar and Thailand. Our main concern is with forced displacement as a result of political and ethnic conflict; specifically, how the Burmese military regime's desire for "national unity" within Myanmar's "national space" has influenced the militarily inspired displacements of hundreds of thousands of villagers and civilians within the border zones inhabited mostly by so-called "national minorities". We examine the particular problems of the so-called "internally displaced persons" within "national" boundaries compared with the "refugees" and "undocumented migrants" who make it across "international" space into Thailand. We illustrate the ways displaced people are represented by state agencies and the media as "threats" and "transgressors". We consider some of the "long term" aspects of the displacement problem along the Myanmar-Thai border and the vital contribution geographers can make to the study of displacement.  相似文献   

Use of Noise to Augment Training Data: A Neural Network Method of Mineral–Potential Mapping in Regions of Limited Known Deposit Examples     

Warick M. Brown  Tamás D. Gedeon  David I. Groves 《Natural Resources Research》2003,12(2):141-152

One of the main factors that affects the performance of MLP neural networks trained using the backpropagation algorithm in mineral-potential mapping isthe paucity of deposit relative to barren training patterns. To overcome this problem, random noise is added to the original training patterns in order to create additional synthetic deposit training data. Experiments on the effect of the number of deposits available for training in the Kalgoorlie Terrane orogenic gold province show that both the classification performance of a trained network and the quality of the resultant prospectivity map increasesignificantly with increased numbers of deposit patterns. Experiments are conducted to determine the optimum amount of noise using both uniform and normally distributed random noise. Through the addition of noise to the original deposit training data, the number of deposit training patterns is increased from approximately 50 to 1000. The percentage of correct classifications significantly improves for the independent test set as well as for deposit patterns in the test set. For example, using ±40% uniform random noise, the test-set classification performance increases from 67.9% and 68.0% to 72.8% and 77.1% (for test-set overall and test-set deposit patterns, respectively). Indices for the quality of the resultant prospectivity map, (i.e. D/A, D × (D/A), where D is the percentage of deposits and A is the percentage of the total area for the highest prospectivity map-class, and area under an ROC curve) also increase from 8.2, 105, 0.79 to 17.9, 226, 0.87, respectively. Increasing the size of the training-stop data set results in a further increase in classification performance to 73.5%, 77.4%, 14.7, 296, 0.87 for test-set overall and test-set deposit patterns, D/A, D × (D/A), and area under the ROC curve, respectively.  相似文献   

Statistical properties of reflection traveltimes in 3-D randomly inhomogeneous and anisomeric media   总被引：1，自引：0，他引：1  

Yu. A. Kravtsov  T. M. Müller  S. A. Shapiro  S. Buske 《Geophysical Journal International》2003,154(3):841-851

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