首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
方向关系与距离关系的定性描述与推理   总被引:12,自引:0,他引:12  
由于空间问题固有复杂性和不确定性,空间关系的描述和推理普遍采用定性的方法,方向关系和距离关系是两类重要的空间关系,用以确定空间目标的方位,当前方向和距离关系分别使用各自独立的描述推理模型,限制了推理的准确度,而人们对空间目标方位的确定通常是同时考虑目标的方向和距离,在形式化定性描述方向关系和距离关系推理的基础上,将方向关系和距离关系的推理结合起来,形成方向关系和距离关系的集成组合运算,方向和距离关系相互限制,能够进一步准确推断目标的方位,最后,以实例说明方向关系和距离关系的集成组成运算将提高空间目标方位推断的准确度。  相似文献   

2.
方向关系与距离关系的定性描述与推理   总被引:2,自引:0,他引:2  
由于空间问题固有的复杂性和不确定性 ,空间关系的描述和推理普遍采用定性的方法 .方向关系和距离关系是两类重要的空间关系 ,用以确定空间目标的方位 .当前方向和距离关系分别使用各自独立的描述推理模型 ,限制了推理的准确度 .而人们对空间目标方位的确定通常是同时考虑目标的方向和距离 .在形式化定性描述方向关系和距离关系推理的基础上 ,将方向关系和距离关系的推理结合起来 ,形成方向关系和距离关系的集成组合运算 ,方向和距离关系相互限制 ,能够进一步准确推断目标的方位 .最后 ,以实例说明方向关系和距离关系的集成组合运算将提高空间目标方位推断的准确度 .  相似文献   

3.
方向关系推理是定性空间推理领域的一项重要的研究内容,得到了国内外许多学者的关注,其中,主方向关系的合成又是方向关系推理的基石。本文以Goyal和Egenhofer提出的“井”方向关系模型为基础,考虑了关系合成中的两种情况,即基于一致性的合成(Consistency-based Composition)与实体论合成(Existential Composition),给出了一种基于一致性的关系合成的新方法,同时从理论上证明了该方法的正确性。  相似文献   

4.
以往对方向关系的研究主要集中在方向关系的形式化描述方面,忽略了空间关系认知与空间关系可视化的联系,因而只反映了空间关系认知的一个方面.在方向关系形式化描述的基础上,探讨了方向关系推理的可视化,从而将空间关系认知与空间信息可视化有机地联系起来.  相似文献   

5.
约束满足问题是人工智能的一个研究领域,诸如查找、规划等问题都可转化为约束满足问题利用约束满足方法加以有效地解决。方向关系是空间关系的重要组成部分,用以确定空间对象的方位。本文应用约束满足问题的方法,利用空间方向关系约束的谓词形式构造X图和Y图来检查约束的一致性,给出了进行空间方向关系推理的一个算法。  相似文献   

6.
方向关系描述GIS中对象之间的空间关系。3D-GIS中单方向关系间定性推理共有27×27=729结果,方向关系定性推理的规律性研究是研究单方向关系定性推理的提升。本文采用单纯形数据模型,用基于投影的27方向关系描述模型,详细研究3D-GIS中方向关系间定性推理的规律,最后得出一些重要结论。  相似文献   

7.
侯睿 《科技资讯》2007,(22):53-54
空间关系是GIS的重要理论问题之一,在GIS数据建模、空间查询、空间分析、空间推理、制图综合、地图理解等过程中起着重要作用.方向关系的是一类重要空间定性关系.文章首先讨论了方向关系定性表示,然后着重讨论回跳搜索算法和基于方向关系组合运算表的定性推理,最后给出一个基于回跳搜索的方向关系组合运算表的定性推理算法.  相似文献   

8.
模糊性区域的空间目标之间的空间关系描述与推理问题在近年来成为GIS界研究的一个热点.本文首先讨论了模糊区域的定义和边界问题,然后把描述确定性区域的9交模型引入到模糊区域,建立了二维空间中描述模糊区域之间的9交模型,最后提出了基于空间方向关系和空间拓扑关系的组合推理方法.  相似文献   

9.
提出了一组用于描述对象空间关系的特征不变量,可以证明,该特征不变量描述的空间关系具有平移、旋转和放缩不变性。基于该特征不变量,还给出了对象空间关系的相似性判别公式,实验表明,利用相似性判别公式能快速而有效地进行对象空间关系的相似性匹配,为对象空间关系的描述及相似性检索提供了一个有效的度量途径。  相似文献   

10.
以往对方向关系的研究主要集中在方向关系的形式化描述方面 ,忽略了空间关系认知与空间关系可视化的联系 ,因而只反映了空间关系认知的一个方面 .在方向关系形式化描述的基础上 ,探讨了方向关系推理的可视化 ,从而将空间关系认知与空间信息可视化有机地联系起来  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
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   

13.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
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   

18.
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   

19.
20.
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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号