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1.
基于GIS的空间插值方法研究   总被引:47,自引:0,他引:47  
对地理信息系统空间数据分析中的空间数据插值方法从广义的角度分为点的插值和面的插值进行了论述,讨论了点与面的各种插值方法的理论基础、算法以及应用方式,并对空间插值的应用与推广及相关的问题进行了阐述.指出在运用空间插值方法时,要得到理想的空间插值效果,必须针对不同研究区的实际情况,对实测数据样本点进行充分分析,反复试验比较,以选择最佳的方法,并在运用一般插值方法的基础上,依据自身需要及学科的特点,对插值方法进行改进,进而提出适合各学科研究的更优的空间插值方法.  相似文献   

2.
提出一种基于马尔柯夫随机场模型和多层前馈神经网络进行纹理分割的方法,利用二阶高斯MRF模型对图像纹理进行描述,采用最小平方误差方法进行参数估计,将估计参数作纹理的特征向量,并且利用改进的BP算法对特征进行分类。对纹理图像进行了实验表明,与常规距离方法相比,采用这种方法进行纹理分割能取得更好的效果。  相似文献   

3.
卫星结构蜂窝夹层板的等效计算   总被引:29,自引:1,他引:29  
在利用MSC/NASTRAN对卫星结构进行有限元计算时,必须对蜂窝夹层板进行预先的等效处理,等效处理的合理与否将直接影响到计算结果的可信度.为此,研究了3种不同的等效方法,即三明治夹心板理论、蜂窝板理论以及等效板理论,其中三明治夹心板理论方法只对蜂窝夹芯进行等效,而蜂窝板理论和等效板理论方法则是对整个蜂窝夹层板进行等效.分别采用这3种等效方法,对某铝蜂窝夹层板的2种工况进行了模态分析,并将计算结果进行了比较.结果表明,运用等效方法的计算结果非常接近于解析解,证实了等效处理方法的合理性和正确性.  相似文献   

4.
一种改进的小波变换信号消噪方法   总被引:5,自引:0,他引:5       下载免费PDF全文
根据小波阈值消噪方法的步骤及特点提出一种新的消噪方法——小波系数放大法,并对该方法进行仿真对比实验。该方法在运用小波变换对含噪信号进行消噪前,先对信号进行小波级数分解,对其中的低频系数和高频系数进行适当的放大,然后对信号采取阈值消噪法进行消噪,最后运用小波变换对所得到的小波系数进行适当的宿小,并将其重构。仿真实验结果表明,小波系数放大法消噪后信号的均方根误差有很大的降低,信噪比提高。该方法优于一般的消噪方法。  相似文献   

5.
为了对DTI图像进行正则化,采用了Gaussian-MRF模型。正则化方法根据Bayes准则对图像灰度值进行最大后验(MAP)估计,估计采用模拟退火方法进行,退火温度采用指数冷却进度表。通过对不同加权梯度下的同一层图像(一共7幅)同时进行正则化实验,结果表明该方法能够改善图像的噪声性能。把本正则化方法的结果与对张量场直接进行正则化的结果进行比较,表明采用本方法能够更加有效地减小噪声影响。通过把指数冷却进度表和对数冷却进度表的结果进行比较,表明采用指数温度能够在更短的时间内获得更好的正则化效果。  相似文献   

6.
高速公路车流量预测方法的研究   总被引:1,自引:0,他引:1  
阐述了高速公路车流量预测研究的意义,并对各种预测方法进行了详细的讨论。通过一个高速公路的实例,对这些预测方法进行了对比分析,并对这些预测方法在高速公路车流量预测问题上的适用性进行了归纳总结。  相似文献   

7.
从市场响应的角度进行制造企业的敏捷性研究,根据制造企业敏捷性研究的框架模型,提出了制造企业敏捷性的研究方法,应用社会统计方法中的主成分分析对数据进行分析,并应用这种方法对一制造企业进行了实证研究。  相似文献   

8.
对轨道电路故障判断分析方法的探讨   总被引:1,自引:0,他引:1  
陆晓东 《甘肃科技》2003,19(5):39-41
经过实际验征,对轨道电路故障的判断得出了一种简学易引的方法,文章即对此方法进行说明,以对实际问题进行指导。  相似文献   

9.
低信噪比神经元锋电位信号的分类方法   总被引:1,自引:1,他引:1  
基于离散序列小波变换和主元分析,对低信噪比的神经元锋电位信号提出了新的分类方法。通过对原始信号进行尖峰检测,获得尖峰信号样本,对每个样本进行离散序列小波变换之后,再对小波变换系数进行主元分析,选取主元进行聚类,实现对原始信号的分类。将该方法应用于多电极细胞外记录的小鸡视网膜神经节细胞电活动信号分析,并据此推断出某电极附近的神经节细胞的个数。仿真结果表明,在低信噪比情况下,该方法比单纯通过小波变换进行分类的方法更有效。  相似文献   

10.
基于面向对象模型库的多模型决策支持系统   总被引:3,自引:0,他引:3       下载免费PDF全文
针对面向对象模型管理方法中的两个问题,对DSS中的知识进行了重新划分,对知识的管理方法进行了阐述,同时引入模型置信度的概念,提出了多模型决策的实现方法。  相似文献   

11.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

12.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

15.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

16.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

17.
18.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

19.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

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