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1.
主要研究广义近似空间上粗糙近似算子的扩展模型.首先,将Cattaneo提出的抽象近似空间理论具体运用于广义近似空间中的粗糙集模型研究,利用空间中双论域间的二元关系,导出指定论域上的一个Brouwer-正交补算子,据此算子构造性地定义了指定论域上的两对粗糙近似算子.然后,研究了新算子的基本性质和代数表示,将它们与已有近似算子进行对比,指出它们的异同,给出它们之间的大小顺序关系.最后,研究了新近似算子和已有近似算子的等价性,给出它们与邻近算子之间等价的条件,讨论了等价条件之间的关系.  相似文献   

2.
研究了有限论域上的广义近似空间与拓扑空间之间的关系。首先,给出了粗糙隶属函数,拓扑隶属函数的概念。其次,借助粗糙隶属函数刻画了的上下近似算子,借助拓扑隶属函数刻画了的内部闭包算子。再次,利用隶属函数分别从拓扑,二元关系出发构造了关系,拓扑,最终证得拓扑空间与关于自反传递关系的近似空间一一对应。  相似文献   

3.
变精度粗糙集β下近似属性约简   总被引:1,自引:0,他引:1  
从属性集角度研究变精度粗糙集模型的属性约简问题,在对象集上定义了一种β下近似二元关系,并利用这种关系建立了属性集及其幂集上的等价关系,由此产生依赖空间。同时利用定义的二元关系和依赖空间给出了变精度粗糙集的β下近似协调集的判定定理,得到一种保持每个决策类的β下近似不变的属性约简方法。最后通过实例验证方法的有效性。  相似文献   

4.
基于集值映射的近似算子   总被引:4,自引:0,他引:4  
介绍了Gomolinska提出的基于集值映射的粗糙集模型,证明了基于一般二元关系的广义近似算子以及覆盖近似算子都是基于集值映射的近似算子特例,且多数的近似算子可以借助基本近似算子通过复合运算产生。  相似文献   

5.
本文通过对基于双向s-粗集和一般二元关系R所提出的广义双向s-粗集的分析,提出了变精度广义双向s-粗集,定义了广义双向s-粗集中的多数包含关系,借助引入误差参数α(0≤α〈0.5),给出了变精度广义s-粗集模型及其有关性质定理.通过实例分析并验证了动态系统中由于属性集合的动态迁移特性与变精度参数变化所产生的广义s-粗集的上、下近似,边界和分类近似精度的变化关系.  相似文献   

6.
广义单向S-粗集和它的一般结构   总被引:2,自引:1,他引:2  
基于单向S-粗集和一般二元关系R,本文给出广义单向S-粗集,对广义单向S-粗集的一般结构进行了描述,对广义单向S-粗集的有关性质进行了讨论.广义单向S-粗集为研究一般系统动态的近似特性提供了新的途径和方法.  相似文献   

7.
本文讨论基于逆串行且有性质(P)的广义近似空间与近似空间的联系;通过构造方法说明对称关系下的广义近似空间都对应于某个逆串行关系的广义近似空间,进而讨论对称的且有性质(P)的广义近似空间与近似空间的联系;最后讨论了自反且传递关系下广义近似空间的拓扑性质.  相似文献   

8.
模糊粗糙集是目前数据挖掘领域关注的热点之一,作者在Pawlak粗糙集模型基础上,把一个论域推广为两个论域;把等价关系推广为模糊关系,被近似对象换成模糊集,得到广义模糊粗糙集模型,建立了广义模糊近似空间。在广义模糊近似空间中定义了广义模糊粗糙集上的包含度和相似度,并讨论了此包含度和相似度相关性质。  相似文献   

9.
孔亮 《河南科学》2014,(12):2434-2439
在实赋范线性空间中,给出了广义近似等腰正交和广义近似保等腰正交映射的定义,得到了广义近似保等腰正交线性映射的一些充分条件,证明了非零广义近似保等腰正交线性映射有界并且是下有界的,推广了近似保等腰正交线性映射的定义和结论.  相似文献   

10.
关于广义完全分配格的一个注记   总被引:2,自引:1,他引:1  
证明了在广义完全分配格中二元关系ρ满足幂等性,即ρ^2=ρ,借助于二元关系ρ给出了广义完全分配格的几个刻划。  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.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
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   

14.
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   

15.
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   

16.
17.
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   

18.
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   

19.
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   

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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