基于MPI瞬变电磁测深一维反演并行算法探究

在瞬变电磁测深反演中运用并行技术可以减少计算时间,提高反演的运算效率。MPI（Message Passing Interface）是目前最重要的并行编程工具,它具有移植性好、功能强大、效率高等多种优点。这里基于在Windows系统下使用FORTRAN和MPICH2相结合的开发工具,编写瞬变电磁并行算法程序,对瞬变电磁一维采用直接反演法,通过理论模型对该算法进行试算,计算结果证明了该算法的正确性、高效性和稳定性。     

城市空间智能计算平台研究

该文提出了空间智能平台的概念,阐述了其研究意义和内容,明确了空间智能计算平台核心计算模型的建模对象和目标。在此基础上,分析了宏观数学模型、群体行为模型两种用来构建空间活动模型的建模方法以及适用于空间活动分析的物理环境建模技术。从融合多尺度行为模型、构建城市日常生活模型、验证和校验核心模型以及平衡效率和效果4方面探讨了构建空间智能计算平台的关键技术。从实际功能看,城市空间智能平台是联系宏观复杂问题和微观机制的桥梁,是分析城市问题的工程化实验平台,具有广阔的应用前景。     

可调节经线收敛度和经纬线间隔的伪圆柱投影

令纬度ψ<,j>转换为ψ<,j>后,中央经线方程用一个ψ<,j>的7次幂方程表示,中央经线方程的系数关联着纬线间隔.令经度λ<,i>转换为ξ<,i>后,赤道方程用一个ξ<,i>的7次幂方程表示,赤道方程的系数关联着经线间隔.经线的收敛度由经线方程的收敛系数调节.由此构建可调节经线收敛度和经纬线间隔的伪圆柱投影.用一实例...     

Modelling real earthquake activity with reverse engineering based on evolutionary computation methods

Hazard assessment of dangerous natural phenomena is critical because of their evident results concerning loss of human life and property, especially in dense populated areas. Earthquakes are probably the most devastating phenomenon since their immediate and long-term consequences are severe. This study is focused on the earthquake data analysis in different regions of Greece, characterised by different seismicity levels. In specific, a novel model is proposed based on evolutionary computation methods, such as symbolic regression by genetic programming and genetic algorithms in order to elucidate preliminary hidden mathematical relations and patterns found in the seismological signals under study. Furthermore, the model is calibrated using reverse engineering and closes the loop from the data collection to initial hypothesis. In this way, the model formation is achieved. The presented simulation results qualitatively and quantitatively reveal some of the fundamental characteristics of each studied geographical region located in Greece that stem from its geodynamic properties.     

Shuffled Complex Evolution model calibrating algorithm: enhancing its robustness and efficiency

Shuffled Complex Evolution—University of Arizona (SCE‐UA) has been used extensively and proved to be a robust and efficient global optimization method for the calibration of conceptual models. In this paper, two enhancements to the SCE‐UA algorithm are proposed, one to improve its exploration and another to improve its exploitation of the search space. A strategically located initial population is used to improve the exploration capability and a modification to the downhill simplex search method enhances its exploitation capability. This enhanced version of SCE‐UA is tested, first on a suite of test functions and then on a conceptual rainfall‐runoff model using synthetically generated runoff values. It is observed that the strategically located initial population drastically reduces the number of failures and the modified simplex search also leads to a significant reduction in the number of function evaluations to reach the global optimum, when compared with the original SCE‐UA. Thus, the two enhancements significantly improve the robustness and efficiency of the SCE‐UA model calibrating algorithm. Copyright © 2008 John Wiley & Sons, Ltd.     

岩石爆破的相对损伤与损伤累积计算

为了便于工程应用,利用损伤变量定义,确定既真实反映力学作用过程,又易于获取和进行客观度量损伤变量的一种方法。通过提出的相对损伤概念,用相对损伤变量表示含损伤材料在载荷作用下损伤扩展程度和不同部位的相对损伤程度,使衡量受力作用程度的损伤变量确定更易实现。同时,提出了一种基于裂纹扩展的损伤累积计算方法,并用实例计算说明了其合理可行。     

利用FFT技术计算大地水准面高若干问题研究

本文首先从普通二维 FFT算法的基本定义和要求出发 ,深入分析和比较了大地水准面二维平面和二维球面 FFT算法的特点和差异 ,找出了影响二维球面 FFT计算精度的主要误差源 ,并给出了二维球面 FFT计算公式的改进形式。在此基础上 ,本文详细分析讨论了参考场选取、积分球冠半径确定以及核函数改化对大地水准面计算结果的作用和影响。最后 ,本文利用全国 5′× 5′实测重力异常对我国海陆大地水准面进行了试算 ,并将计算结果分别同陆上GPS水准和海上卫星测高观测值作了比较。     

圆形建筑物倾斜观测的新方法

基于全站仪和光电测距仪,本文提出了圆形建筑物倾斜观测的新方法,并推导出了相应的计算公式。     

科学计算程序库WHIGG F90 LIB及其地学应用

WHIGG F90LIB(WFL)是一款用FORTRAN90语言编写的用于地球学科的计算程序库。应用WFL可以减少重复性编程,方便地解决科学计算中数据的预处理问题,结合多种分析方法,对科学问题进行定量分析。利用WFL在地球重力场、气候涛动和数字信号处理3个方面的应用实例,以验证WFL在科学计算中应用的有效性。