基于RDBMS的积件技术的应用研究     

李毅心 《成都信息工程学院学报》2006,21(2):206-209

积件技术是教学软件发展的方向，探讨了用Power Builder前台结合SQL Server关系数据库后台进行多媒体教学积件管理的应用模式，并结合具体教学示例，进行了分析说明。  相似文献   

APPLICATION OF GEOGRAPHICAL PARAMETER DATABASE TO ESTABLISHMENT OF UNIT POPULATION DATABASE   总被引：1，自引：1，他引：0  

DONG Chun  ZHAO Rong  LIU Ji-ping  WANG Gui-xin  WU Xi-zhi 《中国地理科学(英文版)》2003,13(1):34-38

Now GIS is turning into a good tool in handling geographical, economical, and population data, so we can obtain more and more information from these data. On the other hand, in some cases, for a calamity, such as hurricane, earthquake, flood, drought etc., or a decision-making, such as setting up a broadcasting transmitter, building a chemical plant etc., we have to evaluate the total population in the region influenced by a calamity or a project. In this paper, a method is put forward to evaluate the population in such special region. Through exploring the correlation of geographical parameters and the distribution of people in the same region by means of quantitative analysis and qualitative analysis, unit population database (1km× 1km) is established. In this way, estimating the number of people in a special region is capable by adding up the population in every grid involved in this region boundary. The geographical parameters are obtained from topographic database and DEM database on the scale of  相似文献   

The Effect of Solar Activity on the Annual Precipitation in the Beijing Area   总被引：3，自引：0，他引：3  

Juan Zhao  Yan-Ben Han  Zhi-An LiDepartment of Astronomy  Beijing Normal University Beijing  zj@bnu.edu.cnNational Astronomical Observatories  Chinese Academy of Sciences  Beijing 《中国天文和天体物理学报》2004,4(2):189-197

Using continuous wavelet transform, we examine the relationship between solar activity and the annual precipitation in the Beijing area. The results indicate that the annual precipitation is closely related to the variation of sunspot numbers, and that solar activity probably plays an important role in influencing the precipitation on land.  相似文献   

地理信息系统数据库设计     

潘珩 《成都信息工程学院学报》2006,21(4):555-558

首先分析了地理信息系统的组成、地理信息系统数据的特征、地理信息系统数据库的功能，然后进行了中心式导航系统数据库的设计，给出了数据库模型的E-R图，最后描述了空间地理信息的查询功能。  相似文献   

大亚湾沉积物中重金属元素背景值研究     

张银英 《热带海洋学报》1991,(3)

根据大亚湾的自然条件认为,大亚湾沉积物的物质来源是其周围集水区的岩石风化壳,并计算了其风化壳中重金属元素的平均丰度值;又根据沉积物的粒度和深层沉积物重金属元素的含量资料,列方程计算出湾内沉积物中重金属元素的平均含量,根据这两组数据,确定该区域内重金属元素的平均背景值。再通过粒度关系,计算得出大亚湾内各站沉积物中重金属元素的背景值。应用此结果和大亚湾沉积物重金属元素实测结果,计算了由人为影响带入沉积物中的重金属元素含量,了解其受污染的程度。  相似文献   

New Numerical Scheme for Simulation of Hyperbolic Mild-Slope Equation   总被引：2，自引：0，他引：2  

ZHENG Yonghong 《中国海洋工程》2001,(2):185-194

The original hyperbolic mild-slope equation can effectively take into account the combined effects of wave shoaling, refraction, diffraction and reflection, but does not consider the nonlinear effect of waves, and the existing numerical schemes for it show some deficiencies. Based on the original hyperbolic mild-slope equation, a nonlinear dispersion relation is introduced in present paper to effectively take the nonlinear effect of waves into account and a new numerical scheme is proposed. The weakly nonlinear dispersion relation and the improved numerical scheme are applied to the simulation of wave transformation over an elliptic shoal. Numerical tests show that the improvement of the numerical scheme makes efficient the solution to the hyperbolic mild-slope equation. A comparison of numerical results with experimental data indicates that the results obtained by use of the new scheme are satisfactory.  相似文献   

考虑非线性弥散影响的波浪变形数学模型   总被引：3，自引：1，他引：3  

李瑞杰 《海洋学报》2001,23(1):102-108

提出了逼近Kirby和Dalrymple的非线性弥散关系的显式非线性弥散关系的表达式,该显式表达式与他们的非线性弥散关系的精度几乎完全相同.采用显式非线性弥散关系,结合含弱非线性效应的缓坡方程,得到考虑非线性弥散影响的波浪变形数学模型,并对该数学模型进行了数值验证.结果表明,考虑非线性弥散影响的波浪变形数学模型更为精确.  相似文献   

A note on the effects of a thin visco-elastic mud layer on small amplitude water-wave propagation     

Philip L.-F. Liu  I-Chi Chan 《Coastal Engineering》2007

In this note we investigated the effects of a thin visco-elastic mud layer on wave propagation. Within the framework of linear water-wave theory, analytical solutions are obtained for damping rate, dispersion relation between wave frequency and wave number, and velocity components in the water column and mud layer. The wave attenuation rate reaches a maximum value when the mud layer thickness is about the same as the mud boundary layer thickness. Heavier mud has a weaker effect on the wave damping. However, the wave attenuation rate does not always decrease as the elastic shear modulus increases. In the range of small values for elastic shear modulus, the wave attenuation can be amplified quite significantly. The current solutions are compared with experimental data with different wave conditions and mud properties. In general, good agreements are observed.  相似文献   

“数字海底”系统建模中的关键技术研究          下载免费PDF全文

郑彦鹏  刘保华  梁瑞才  毛锋  周文生  苏天赟  傅强 《海洋学报》2007,29(1):81-85

基于“数字海底”系统的理论基础研究和在海底科学应用中的具体实践,提出了“数字海底”的涵义、系统组成和体系结构,对空间数据管理技术、基于XML的WebGIS空间数据表达技术、复杂海底三维建模技术、多源信息的一体化集成显示技术、虚拟现实技术等“数字海底”系统建模中的关键技术进行了探讨,为从事海底资源研究和开发的人员提供各个层次的参考或帮助.  相似文献   

海浪预报产品数据库管理系统开发研究     

许富祥  李凤金  刘煜  戴明瑞  高志华  杨春城  李洁  韦锋余 《海洋预报》2003,20(1):44-51

本文介绍海浪预报产品数据库管理系统，包括数据库管理系统的总体设计，硬软件的配置，数据库管理系统的主要内容和解决的关键技术。该数据库管理系统的建成，提供了我国近海和西北太平洋海浪预报的系统性资料，不仅对提高海浪预报准确率提供基础资料，也给海浪中长期预测预报方法研究和区域海洋学研究带来极大帮助。  相似文献