基于遗传算法的最优证券投资组合模型   总被引：2，自引：0，他引：2  

陈科燕  肖冬荣 《南京气象学院学报》2003,26(5):707-711

为了研究能使风险损失率最小、收益最大的最优证券投资组合问题，首先提出了多目标规划模型，并采用模糊优选法将多目标模型单目标化。随后尝试采用遗传算法来对其求解，给出了模型的遗传算法编码规则和算法步骤。最后通过实例论证了模型的合理性及遗传算法的有效性。  相似文献   

隧道GPS网对横向贯通误差的影响   总被引：4，自引：0，他引：4  

姚连璧  周全基 《测绘学报》1997,26(3):207-212

本文在阐述隧道工程独立坐标系和隧道ＧＰＳ网数据处理方法的基础上推导出ＧＰＳ网对横向贯通误差影响的通用计算公式，分析了隧道ＧＰＳ网基准数据位置对横向贯通误差的影响。  相似文献   

A mixed finite element method for Hele-Shaw cell equations     

J. M. Guevara-Jordan  J. Glimm 《Computational Geosciences》1997,1(1):35-58

A new numerical method to solve the system of equations describing two phase flow in a Hele-Shaw cell is presented. It combines a mixed finite element method, the method of subtraction of the singularity and a front tracking grid in a single computational strategy. This choice of discretization techniques is well motivated by the difficulties present in the system of equations and the physics of the problem. The new method was tested against analytical solutions and also by solving the Saffman–Taylor viscous fingering problem for finite and infinite mobility ratios. In both cases convergence under mesh refinement is achieved for the fingers developed from an initial sinusoidal interface. Finger splitting is observed for low values of the surface tension and high mobility ratio. Different explanations, based in our results, are provided for this phenomenon. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

QN—模型及其在覆盖区资源靶区预测中的应用     

陈永良  杜德文 《吉林地质》1997,16(3):51-56

本文把数量化理论Ⅲ与Ｑ－型非线性映射在机地结合在一起，定义了一种新的数学模型－ＱＮ－模型。详细地介绍了该模型的基本原理和计算步骤，给出了模型在覆盖区资源靶区以预测中应用的实例。  相似文献   

试论会东大银厂铅锌矿找矿模式   总被引：2，自引：0，他引：2  

何端臣  祖世元 《四川地质学报》1997,(3)

对大银厂铅锌矿点分布区的地层、构造和成矿地质背景进行了论述，并与大梁子铅锌矿床作了对比，提出了寻找该类矿床的模式及找寻工业矿体最有希望的地段。找矿方法宜先化探后钻探。  相似文献   

Transport in a 2-D saturated porous medium: A new method for particle tracking   总被引：2，自引：0，他引：2  

Frédérick Delay  Hélène Housset-Resche  Gilles Porel  Ghislain de Marsily 《Mathematical Geology》1996,28(1):45-71

A new method for solving the transport equation based on the management of a large numbe of particles in a discretized 2-D domain is presented. The method uses numerical variables to represent the number of particles in a given mesh and is more complex than the 1-D problem. The first part of the paper focuses on the specific management of particles in a 2-D problem. The method also would be valid for three dimensions as long as the medium can be modeled similar to a layered system. As the particles are no longer tracked individually, the algorithm is fast and does not depend on the number of particles present. The numerical tests show that the method is nearly numerical dispersion free and permits accurate calculations even for simulations of low-concentration transport. Because each mesh is considered as a closed system between two successive time steps, it is easy to add adsorption phenomenon without any problem of numerical stability. The model is tested under conditions that are extremely demanding for its operating mode and gives a good fit to analytical solutions. The conditions in which it can be used to best advantage are discussed.  相似文献   

山东招远北截金矿床地质特征及深部成矿预测   总被引：1，自引：1，他引：1  

颜丹平  万天丰  栾久春 《矿床地质》1997,16(4):365-375

对北截金矿的矿床与矿体地质构造及成矿模式和构造应力场的综合研究表明，北截金矿主要是受ＮＥ向的灵山沟－北截断裂控制，其储矿构造部位与与断裂带小角度斜交的ＮＮＥ向张剪性断裂，矿体主要分布于其中的２号矿带之中，矿体之间呈右行斜列为ＳＷ深部发展；百区内的ＮＷＷ向断裂为成矿后断裂，对矿体有较小的破坏作用；对矿区内Ａｕ、Ａｇ、Ａｓ、Ｍｏ、Ｓｂ、Ｂｉ进行的微量元素原生晕及Ａｇ／Ａｕ、Ａｓ／Ｍｏ与Ｓｂ／Ｂｉ比值分  相似文献   

江西利山金矿床地质特征及控矿构造     

高文亮  聂剑华 《江西地质》1997,11(1):60-68

本文较系统地阐述了利山金矿床的各项地质特征，并重点就控矿构造问题进行了总结讨论，认为ＮＷＷ向断裂带严格控制了所有金矿体的产出。ＮＮＥ、ＮＮＷ向断裂与ＮＷＷ向断裂带的交汇部位控制了富矿段的产出。在此基础上初步探讨了矿床成因及找矿方向，这对该地区的找矿评价和开发均具有实际意义  相似文献   

Methods for Setting up a Three-Dimensional Industrial Surveying System of “Building Blocks Type”     

FENG Wenhao 《地球空间信息科学学报》2004,(3)

1　Methodsfororientatinginitialdirec tioninindustrialsurveyDifferentfromconventionalengineeringsurvey,thedistancebetweenthetwoangle measurementdevicesinindustrialsurveyisnomorethantenmeters.Theaccu racyforthemeasurementofobjectpointsisrequiredtobebetween± ( 0 .0 2～ 0 .0 5～ 0 .2 0 )mm ,sotheaccu racyfortheorientationoftheinitialdirectionoughttobehigh .Theexistingmethodsfororientatingtheinitialdirectionbetweenthetwoangle measurementdevicesincludemethodofusinginnertarget,collimatormethod,metho…  相似文献   

GIS数据辅助下的线状目标自动提取   总被引：2，自引：0，他引：2  

郭海涛张衡  张保明陈江 《测绘学院学报》2004,21(4):275-278

首先介绍了遥感影像中线状目标骨架自动提取的意义和研究现状，然后结合老的GIS数据，提出了一种算法来实现遥感影像中线状目标骨架的自动提取，算法主要包括影像预处理、GIS数据与影像的配准、骨架跟踪、编组连接与数据简化等步骤。最后又利用遥感影像和相应的GIS数据进行了实验，实验证明了算法的可行性和有效性。  相似文献