一类0—1整数规划问题的解法

本文分析了一类特殊的０－１整数规划问题，并给出了一种在特定条件下较分枝定界法和隐枚举法更简便有效的解法，在实例运用中得到了比较简洁、圆满的结果。     

基于二进制粒子群优化算法的线状目标简化

针对如何从线状目标的简化可行解中选取近似最优解的问题,该文基于二进制粒子群优化算法原理,将线状目标的可行解抽象为节点是否取舍两种状态的二进制序列,由粒子群根据个体经验和社会经验判断构成线状目标上的节点取舍,提出并设计了一种简化线状目标的算法。目标函数主要由节点压缩率和矢量偏差确定,文中给出了算法实现的关键步骤。通过与道格拉斯-普克算法作对比实验分析,证明了该算法的有效性,保留了重要的几何特征点,图形有良好的外观视觉效果,且有更高的节点压缩率。     

0-1背包问题的多重分枝-限界算法

建立了0-1背包问题数学模型的一般形式,对通常的分枝一限界算法作了推广,给出了多重分枝一限界算法,有效地解决了具有多个背包的0-1背包问题;也可用于解决某些具有\     

0-1背包问题多重分枝-限界算法的改进

对0-l背包问题多重分枝一限界算法^[1]作了改进。经改进的算法仅用一棵状态空间树描述问题的解空间。引入了虚拟背包的概念,简化了限界函数的计算。新的算法较大地提高了搜索最优解的效率。     

0—1背包问题的多重分枝—限界算法

建立了０－１背包问题数学模型的一般形式，对通常的分枝－限界算法作了推广，给出了多重分枝－限界算法，有效地解决了具有多个背包的０－１背包问题，也可用于解决某些具有“多重”性质的０－１规划问题。     

0—1背包问题多重分枝—限界算法的改进

对０－１背包问题多重分枝－限界算法作了改进，经改进的算法仅用一棵状态空间树描述问题的解空间。引入了虚拟背包的概念，简化了限界函数的计算。新的算法较大地提高了搜索最优解的效率。     

土地利用规划实施评价辅助决策系统的构建

以土地利用数据库和土地利用规划实施评价业务为主线,根据土地利用规划实施评价的数学模型和具体过程,设计了土地利用规划实施评价辅助决策支持系统,通过对评价指标筛选、模型因子和权重选择实现对总体规划实施过程及结果的定性与定量分析,为土地利用规划实施评价过程的自动化提供了有力的技术支持。     

电子政务空间辅助决策系统中数据库性能的优化

Oracle9i数据库系统是一个大型而复杂的运行系统,其运行效率对系统性能至关重要。本文从数据库结构、SQL语句和内存分配等三个方面对Oracle9i数据库性能的优化做了阐述,提出了一些原则和方法。     

基于WebGIS的平安城市视频监控系统的设计与实现

介绍了城市视频监控地理信息系统的基本内容及基于WebGIS的城市视频监控地理信息系统组成,利用SuperMap空间数据库进行城市视频监控点的空间信息和属性信息的存储、可视化查询和修改,为维护社会安全提供了有力的技术保障。     

应急平台中一维洪水演进模型研究

根据应急平台的特点和需求,建立了一维洪水演进数学模型。利用简便易行的基于特征线法的库朗格式求解方程,应用Matlab编制了洪水演进计算程序,并利用其强大的绘图功能实现了计算结果的可视化显示和分析。通过对长江某河段实测资料的建模分析和应用研究,验证了模型的实用性和可靠性。     

Matlab和C#混合编程在SAR图像船只检测中的应用

目前,SAR图像船只检测只能在当前编程软件中实现,无法被其他软件调用,很难在后续开发的软件系统中得到广泛的应用。为此,本文基于C#和Matlab混合编程,开发出了一种可以被调用的SAR图像船只检测界面性应用窗体。该窗体运行后,生成K分布、G^0分布和直方图统计模型的概率密度函数曲线和相应的检测结果图像,通过比较,可判别出K分布更适合应用于SAR图像的船只检测中。     

地壳垂直运动的均衡理论及其分析模型

介绍了地壳垂直运动均衡理论并根据全球通量均衡假说建立了壳垂直运动的动力学模型（具有第二边值条件的Laplace方程），在球面近似下运用该模型拟了渤海湾地区的地壳垂直运动形变场并编制了等值线图，获得了满意的结果。     

有限元法逼近局域大地水准面的数学模型

顾及到大地水准面的物理特性,依据其在局部所应满足的数学物理方程,讨论了有限元法逼近局域大地水准面的数学思想,给出了相应的数学模型.     

ArcGIS建模在集体土地所有权数据库质检中的运用

农村集体土地所有权确权登记发证成果逐年进行更新备案,为确保更新后的数据库成果符合地籍数据库入库标准,依据数据标准设计了正确、全面的质检规则,基于质检规则并利用ArcGIS Model Builder、Python语言开发了数据库质检软件。本文以怀集县为例,通过该软件实现了入库前自动化、可视化检查,通过ArcGIS Server将软件设计的质检模型发布为GP服务,可为国土资源日常管理提供强大的工具保障。     

3维地面模型的数据采集方式--日本砂防项目的思考

从日本全国范围的砂防项目数据生产出发,研究生产、检查真3维数据的技术、软件,并提出我国的3维数据生产的方法及其意义。     

The Effects of Quality Control on Decreasing Error Propagation in the LandScan USA Population Distribution Model: A Case Study of Philadelphia County

LandScan USA is a 90 m population distribution model that is used for a variety of applications, including emergency management. Models should have a measure of accuracy; however, the accuracy of population distribution models is difficult to determine due to the inclusion of multiple input datasets and the lack of quantifiable, observable (validated) data to confirm model output. Validated data enables quantification of: (1) overall model accuracy and (2) changes in model output at different levels of quality control. This article examines the effect of quality control for two national school datasets incorporated as input in LandScan USA for Philadelphia County, Pennsylvania; which had a local, validated school dataset available. The effect of each stage of quality control efforts utilized throughout the LandScan USA process were assessed to determine what level of quality control was required to have a statistically significant change of the model's population distribution. The typical level of quality control for LandScan USA resulted in 36% of schools being moved to the correct location and 20% of missing student enrollments were found, compared to 87% and 98% respectively for the validated dataset. The costs of increasing quality control resulted in a six-fold increase in labor time; however, the additional quality control did not produce statistically significant improvements in the LandScan USA model. Thus, typical quality control efforts for schools in LandScan USA produced a population distribution similar to the validated level of quality control, and can be applied with confidence for policy, planning, and emergency situations.     

The effect on the geoid of lateral topographic density variations

Gravimetric geoid determination by Stokes formula requires that the effects of topographic masses be removed prior to Stokes integration. This step includes the direct topographic and the downward continuation (DWC) effects on gravity anomaly, and the computations yield the co-geoid height. By adding the effect of restoration of the topography, the indirect effect on the geoid, the geoid height is obtained. Unfortunately, the computations of all these topographic effects are hampered by the uncertainty of the density distribution of the topography. Usually the computations are limited to a constant topographic density, but recently the effects of lateral density variations have been studied for their direct and indirect effects on the geoid. It is emphasised that the DWC effect might also be significantly affected by a lateral density variation. However, instead of computing separate effects of lateral density variation for direct, DWC and indirect effects, it is shown in two independent ways that the total geoid effect due to the lateral density anomaly can be represented as a simple correction proportional to the lateral density anomaly and the elevation squared of the computation point. This simple formula stems from the fact that the significant long-wavelength contributions to the various topographic effects cancel in their sum. Assuming that the lateral density anomaly is within 20% of the standard topographic density, the derived formula implies that the total effect on the geoid is significant at the centimetre level for topographic elevations above 0.66 km. For elevations of 1000, 2000 and 5000 m the effect is within ± 2.2, ± 8.8 and ± 56.8 cm, respectively. For the elevation of Mt. Everest the effect is within ± 1.78 m.