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1.
<正>针对城市地下综合管线和专业管线空间数据匹配中语义表达不足、语义相似性计算方法简单及匹配质量不高等问题,提出一种顾及管线空间特征的概念语义相似性方法.首先列举管线概念属性项以表达概念语义,分析管线实体拓扑特征确定实体空间关联情况,融合其他特征建立管线本体;然后从管线信息概念内涵出发,提出基于概念语义的管线空间数据匹配模型,其中利用概念属性、空间特征及本体层次结构匹配指标,结合权重信息计算管线实体相似度大小确定匹配实体.实验结果表明,该方法能更合理地计算管线实体间的相似度,明显提升管线空间数据匹配的质量.  相似文献   

2.
现势性是发挥数据应用价值的关键。鉴于在地理要素数据匹配过程中,常常因为分类标准不同或地图综合处理等原因而产生要素属性间的语义异质性,该文试图通过引入本体语义技术解决语义异质性问题,利用属性枚举的方法表达地理要素类别语义,构建地理要素分类本体结构;同时将地物属性信息划分为要素类别信息、地物名称信息以及辅助信息3个部分,提出了语义支持的地理要素属性相似性模型。该模型从概念语义内涵的角度计算地理要素类别的相似性;从地物名称字面出发计算地物名称相似度;根据不同的辅助属性类型计算辅助属性相似度。实验结果表明,同尺度多时态与跨尺度相同时间版本环境下,所提出的模型可有效合理地评价候选地物间的属性相似性,较好地为地理数据匹配提供支持。  相似文献   

3.
以流程工厂协同设计应用为背景,提出基于允许误差的最大语义图匹配(MSMGE)算法的异构图形数据近似语义匹配模型。利用类无向图来描述2D和3D异构图形数据的工程属性和拓扑关系,消除了图形信息的异构性,并建立各种类实体的属性标签词典来消除2D和3D属性信息的异构性,用语义表达式来表示类无向图顶点和边的语义关系,将异构图形匹配转化为近似语义图匹配。通过基于工程语义对类无向图进行语义分割和基于最大公共序列算法的语义表达式比较、语义规整和语义裁剪等方法,降低了匹配搜索空间,提高了近似语义图匹配效率,实现了近似语义图匹配判断。该研究已经在流程工厂设计软件中得到较好地应用。  相似文献   

4.
目的 多尺度空间关系一致性评价是多尺度空间数据冲突检测或数据匹配的重要环节,现有方法主要集中于相同或相近比例尺空间关系的相似性计算,对尺度跨度较大、发生维度变化情形的一致性评价考虑较少,且定性的概念距离度量方法难以适用于具有维度差异的多尺度空间数据。针对上述问题,提出一种顾及降维的多尺度空间关系广义一致性度量方法。方法 首先,引入同名对象概念,分析多尺度范畴下同名对象的表现特征。考虑到维度变化对空间关系的影响,结合并扩展已有的空间关系度量方法,分别提出了广义的拓扑关系、方向关系、距离关系相似性度量方法。然后,构建小尺度场景的同名对象邻近关系图,为减少一致性计算代价,依据不同空间关系特点将邻近关系图化简为各类空间关系邻近图。最后,通过依次计算各类空间关系的相似性值和联合相似性值来判断多尺度场景空间关系表达的一致性。结果 通过对1:1万基础地理数据和1:5万派生数据进行空间关系相似性的定量计算分析,并与现有概念距离方法进行比较,验证了本文方法能更精确地度量尺度跨度较大的空间关系一致性。结论 该评价方法具有广泛适用性,可用于辅助地图综合、多尺度空间数据匹配以及多尺度空间数据建库等过程。  相似文献   

5.
局部Gist特征匹配核的场景分类   总被引:5,自引:1,他引:4       下载免费PDF全文
针对场景分类任务中全局Gist特征粒度较为粗糙的问题,提出一种基于稠密网格的局部Gist特征描述,利用空间金字塔结构加入空间信息,通过引入RGB颜色空间加入颜色信息,并基于词汇包(BOW)模型设计一种高效匹配核来度量局部特征间的相似性,核化特征匹配过程,使用线性SVM完成场景分类.实验考察了不同尺度、方向、粒度和不同匹配核的局部Gist特征以及训练样本集的大小对分类结果的影响,并通过在OT场景图像集上与全局Gist特征和稠密SIFT特征的场景分类结果进行比较,充分说明了本文特征构造方法和分类模型的有效性.  相似文献   

6.
提出一种基于空间金字塔分块与PLSA方法相结合的场景分类方法.该方法首先通过空间金字塔分块的方式来构建图像区域集合,然后利用概率潜在语义分析(PLSA)从图像的区域集合中发现潜在语义模型,最后根据潜在语义模型找出所有图像区域中潜在语义出现概率来构建区域潜在语义特征,并使用该特征构建SVM模型进行场景分类.在13类场景图像上的试验表明,和其他方法相比,该方法中不需要进行大量的手工标注,而且具有更高的分类准确率.  相似文献   

7.
模式匹配在很多数据库相关领域中有着广泛的应用,例如数据集成、数据空间以及数据仓库。传统的匹配技术主要研究两个属性之间的匹配任务,而忽略了多个属性间的匹配任务。针对这一问题,提出一种基于DBSCAN聚类算法的多模式集成技术。该方法将关注多个属性之间语义对应关系的发现,相对于两个属性之间对应关系的发现,这将是一个更加复杂的问题。主要研究思路是将每个属性看成向量空间中的一个点,然后利用聚类技术将这些属性划分到不同的集合中,在同一个聚类中的属性具有相似的语义。同时,利用Web结构信息源来提高模式匹配结果的质量。最后,通过大量的实验来验证该方法是有效的并具有较好的性能。  相似文献   

8.
现有的空间关键字查询处理模式大都仅支持位置相近和文本相似匹配,但不能将语义相近但形式上不匹配的对象提供给用户;并且,当前的空间-文本索引结构也不能对空间对象中的数值属性进行处理。针对上述问题,本文提出了一种支持语义近似查询的空间关键字查询方法。首先,利用词嵌入技术对用户原始查询进行扩展,生成一系列与原始查询关键字语义相关的查询关键字;然后,提出了一种能够同时支持文本和语义匹配,并利用Skyline方法对数值属性进行处理的混合索引结构AIR-Tree;最后,利用AIR-Tree进行查询匹配,返回top-k个与查询条件最为相关的有序空间对象。实验分析和结果表明,与现有同类方法相比,本文方法具有较高的执行效率和较好的用户满意度;基于AIR-Tree索引的查询效率较IRS-Tree索引提高了3.6%,在查询结果准确率上较IR-Tree和IRS-Tree索引分别提高了10.14%和16.15%。  相似文献   

9.
产品装配体模型的空间结构相似性检索方法   总被引:1,自引:0,他引:1  
针对因未考虑装配体空间结构而导致的检索结果不符合预期的问题,提出一种基于空间结构匹配的装配体模型检索方法.在运用空间特征点集表示装配体模型的基础上,提出了基于空间点集匹配方法的装配体相似度算法,综合零件属性相似度、零件空间位置相似度得到了装配体相似度.实验结果证明,该方法能够有效地实现产品装配体的相似性检索.  相似文献   

10.
吴锐  刘宇  冯凯 《计算机应用》2021,41(2):372-378
针对行人属性识别任务中不同属性对特征粒度和特征依赖性的需求不同的问题,提出了一种基于由空间自注意力机制和通道自注意力机制组成的双域自注意力机制的行人属性识别模型。首先,使用ResNet50作为骨干网络,提取出具有一定语义信息的特征;然后将得到的特征分别输入到双分支网络中,提取具有空间依赖性与语义相关性的自注意力特征以及整体性信息的全局特征;最后,融合双分支的特征,并利用批归一化(BN)和加权损失的策略降低行人属性样本不平衡的影响。在两个行人属性数据集PETA和RAP上的实验结果表明,所提出的模型比基准模型的平均准确率指标分别提高了3.91个百分点和4.05个百分点,在已提出的行人属性识别模型中具有较强的竞争力。基于双域自注意力机制的行人属性识别方法可在监控场景下对行人进行结构化描述,提高行人分析和检索等任务的准确度和效率。  相似文献   

11.
在交通领域中,传统的交通时空数据分析方法存在拥堵路口的时空数据相似性检索效率低、可靠性差的问题,从空间场景相似度和动态数据相似度等角度出发,提出一种基于时空分析的交通路口相似度计算方法.该方法由交通路口静态数据模型和动态数据模型构成,路口静态数据模型将交通路口作为空间场景,计算目标路口与数据库路口的空间场景相似度,路口动态数据模型根据路口检测器数据的时间属性,创建时序数据库,在时间维度上对路口动态数据进行切片,计算目标路口与数据库路口在相同时段内的相似度,在此基础上构建路口相似度计算模型,对满足相似检索的路口进行排序,以增强检索结果的可靠性.实验结果表明,与时空索引检索算法相比,该方法能够有效提高交通路口检索的准确性,且具有较强的实用性.  相似文献   

12.
数据更新中要素变化检测与匹配方法   总被引:4,自引:0,他引:4  
吴建华  傅仲良 《计算机应用》2008,28(6):1612-1615
在要素类之间缺乏同名实体关联关系的情况下,通过空间分析自动识别出当前要素的同名实体及它们之间的变化信息。在查询当前要素的候选匹配集时,设计了一种基于自定义空间拓扑关系的空间查询方法,缩小了的空间查询范围并减少了查询次数,提高了空间分析的效率;在确定当前要素的同名实体时,提出了基于权重的空间要素相似性计算模型,基于该模型有效地对复杂空间关系下的要素进行了匹配,提高了匹配的准确性。  相似文献   

13.
In recent years, 3D scene construction has become increasingly popular in movies and games. However, it is without doubt that the involved effort is significant, and therefore how to simplify such a process has drawn the attentions from many researchers. More specifically, the construction of a 3D scene consists of two parts: the creation of 3D objects, and their deployment. In general, one possible and popular solution is to reuse previous 3D scene construction results. In this regard, there are least two types of approaches. The first type of approaches places more emphasis on the spatial relationships. In particular, by placing a query box in the current scene and comparing its relationships with other objects under the current scene, a desired object in a previous scene can be retrieved if it shares a similar configuration. However, inappropriate representations of previous spatial relationships may lead to ambiguous or superfluous retrieval results. The second type of approaches focuses on the generation of a single object. A method of such could either start from an initial model and gradually evolve into a more complex/specific one by selecting a similar model in the database, or directly synthesize a new model by a combination of more than one model from the database. This paper proposes a framework that not only integrates the two types of approaches just mentioned, but also unifies the previous two different ways for model construction. In addition, the representation of spatial relationships is further refined so that more desired retrieval results can be obtained, together with a meaningful object class scheme to facilitate the involved interaction for model construction.  相似文献   

14.
Logical Representation of a Conceptual Model for Spatial Data Warehouses   总被引:2,自引:2,他引:0  
The MultiDimER model is a conceptual model used for representing a multidimensional view of data for Data Warehouse (DW) and On-Line Analytical Processing (OLAP) applications. This model includes a spatial extension allowing spatiality in levels, hierarchies, fact relationships, and measures. In this way decision-making users can represent in an abstract manner their analysis needs without considering complex implementation issues and spatial OLAP tools developers can have a common vision for representing spatial data in a multidimensional model. In this paper we propose the transformation of a conceptual schema based on the MultiDimER constructs to an object-relational schema. We based our mapping on the SQL:2003 and SQL/MM standards giving examples of commercial implementation using Oracle 10g with its spatial extension. Further we use spatial integrity constraints to ensure the semantic equivalence of the conceptual and logical schemas. We also show some examples of Oracle spatial functions, including aggregation functions required for the manipulation of spatial data. The described mappings to the object-relational model along with the examples using a commercial system show the feasibility of implementing spatial DWs in current commercial DBMSs. Further, using integrated architectures, where spatial and thematic data is defined within the same DBMS, facilitates the system management simplifying data definition and manipulation.
Esteban ZimányiEmail:
  相似文献   

15.
A key characteristic of video data is the associated spatial and temporal semantics. It is important that a video model models the characteristics of objects and their relationships in time and space. J.F. Allen's (1983) 13 temporal relationships are often used in formulating queries that contain the temporal relationships among video frames. For the spatial relationships, most of the approaches are based on projecting objects on a two or three-dimensional coordinate system. However, very few attempts have been made formally to represent the spatio-temporal relationships of objects contained in the video data and to formulate queries with spatio-temporal constraints. The purpose of the work is to design a model representation for the specification of the spatio-temporal relationships among objects in video sequences. The model describes the spatial relationships among objects for each frame in a given video scene and the temporal relationships (for this frame) of the temporal intervals measuring the duration of these spatial relationships. It also models the temporal composition of an object, which reflects the evolution of object's spatial relationships over the subsequent frames in the video scene and in the entire video sequence. Our model representation also provides an effective and expressive way for the complete and precise specification of distances among objects in digital video. This model is a basis for the annotation of raw video  相似文献   

16.
Scene Parsing Using Region-Based Generative Models   总被引:1,自引:0,他引:1  
Semantic scene classification is a challenging problem in computer vision. In contrast to the common approach of using low-level features computed from the whole scene, we propose "scene parsing" utilizing semantic object detectors (e.g., sky, foliage, and pavement) and region-based scene-configuration models. Because semantic detectors are faulty in practice, it is critical to develop a region-based generative model of outdoor scenes based on characteristic objects in the scene and spatial relationships between them. Since a fully connected scene configuration model is intractable, we chose to model pairwise relationships between regions and estimate scene probabilities using loopy belief propagation on a factor graph. We demonstrate the promise of this approach on a set of over 2000 outdoor photographs, comparing it with existing discriminative approaches and those using low-level features  相似文献   

17.
Due to the increasing popularity of spatial databases, researchers have focused their efforts on improving the query processing performance of the most expensive spatial database operation: the spatial join. While most previous work focused on optimizing the filter step, it has been discovered recently that, for typical GIS data sets, the refinement step of spatial join processing actually requires a longer processing time than the filter step. Furthermore, two-thirds of the time in processing the refinement step is devoted to the computation of polygon intersections. To address this issue, we therefore introduce a novel approach to spatial join optimization that drastically reduces the time of the refinement step. We propose a new approach called Symbolic Intersect Detection (SID) for early detection of true hits. Our SID optimization eliminates most of the expensive polygon intersect computations required by a spatial join by exploiting the symbolic topological relationships between the two candidate polygons and their overlapping minimum bounding rectangle. One important feature of our SID optimization is that it is complementary to the state-of-the-art methods in spatial join processing and therefore can be utilized by these techniques to further optimize their performance. In this paper, we also develop an analytical cost model that characterizes SIDs effectiveness under various conditions. Based on real map data, we furthermore conduct an experimental evaluation comparing the performance of the spatial joins with SID against the state-of-the-art approach. Our experimental results show that SID can effectively identify more than 80% of the true hits with negligible overhead. Consequently, with SID, the time needed for resolving polygon intersect in the refinement step is improved by over 50% over known techniques, as predicted by our analytical model.  相似文献   

18.
In this paper, we propose a computational model of the recognition of real world scenes that bypasses the segmentation and the processing of individual objects or regions. The procedure is based on a very low dimensional representation of the scene, that we term the Spatial Envelope. We propose a set of perceptual dimensions (naturalness, openness, roughness, expansion, ruggedness) that represent the dominant spatial structure of a scene. Then, we show that these dimensions may be reliably estimated using spectral and coarsely localized information. The model generates a multidimensional space in which scenes sharing membership in semantic categories (e.g., streets, highways, coasts) are projected closed together. The performance of the spatial envelope model shows that specific information about object shape or identity is not a requirement for scene categorization and that modeling a holistic representation of the scene informs about its probable semantic category.  相似文献   

19.
Spatial processes and their interactions are fundamental in explaining the complex behavior of real world systems. Current GIS describes space based on map layers and by means of either the vector or raster model. However, current vector and raster models cannot dynamically maintain topological relationships between spatial entities while these are changing rapidly in the real world. This makes current GIS incapable of modeling dynamic spatial processes. In this paper, the development of a process-based model is described. The model is developed based on spatial system theory and the Voronoi spatial model. First, the paper discusses spatial system theory, which forms the theoretical background for the model. Second, the Voronoi spatial model is adopted to describe spatial processes; it is more efficient than conventional vector and raster models. Third, the paper presents the capabilities of the model in one application.  相似文献   

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