对基于R-Tree的空间连接代价模型进行了探讨,主要研究了HUANG Y W提出的空间连接代价模型。利用最优/最差选择策略降低该算法的时间复杂度,对基于缓冲区的代价模型提出了改进后的评估公式,通过实验验证了改进后的模型比原模型提高了评...对基于R-Tree的空间连接代价模型进行了探讨,主要研究了HUANG Y W提出的空间连接代价模型。利用最优/最差选择策略降低该算法的时间复杂度,对基于缓冲区的代价模型提出了改进后的评估公式,通过实验验证了改进后的模型比原模型提高了评估的精确度。展开更多
In view of the shortage of the spatial skyline query methods(SSQ methods) in dealing with the problem of skyline query in multidimensional space, a spatial skyline query method based on Hilbert R-tree in multidimensio...In view of the shortage of the spatial skyline query methods(SSQ methods) in dealing with the problem of skyline query in multidimensional space, a spatial skyline query method based on Hilbert R-tree in multidimensional space is proposed. This method takes the advantages of Hilbert R-tree which combines R-tree and Hilbert curve with high efficiency and dimensionality reduction. According to the number of query points, the proposed method in static query point environment is divided into single query point of SSQ method(SQ-HSKY algorithm) and multi-query points of SSQ method(MQP-HSKY algorithm). The SQ-HSKY method uses the spatial relationship between objects to propose pruning strategy and the skyline set in the filtering and refining process are computed. The MQP-HSKY method uses the topological relationship between data points and query points to prune non skyline points and generate the dominant decision circle to obtain the global skyline set. Theoretical study and experiments confirm the effectiveness and superiority of these methods on the skyline query.展开更多
Multi-level spatial index techniques are always used in large spatial databases. After a general survey of R-tree relevant techniques, this paper presents a novel 2-level index structure, which is based on the schemas...Multi-level spatial index techniques are always used in large spatial databases. After a general survey of R-tree relevant techniques, this paper presents a novel 2-level index structure, which is based on the schemas of spatial grids, Hilbert R-tree and common R-tree. This structure is named H2R-tree, and it is specifically suitable for the indexing highly skewed, distributed, and large spatial database. Algorithms and a sample are given subsequently.展开更多
The characteristic of geographic information system(GIS) spatial data operation is that query is much more frequent than insertion and deletion, and a new hybrid spatial clustering method used to build R-tree for GIS ...The characteristic of geographic information system(GIS) spatial data operation is that query is much more frequent than insertion and deletion, and a new hybrid spatial clustering method used to build R-tree for GIS spatial data was proposed in this paper. According to the aggregation of clustering method, R-tree was used to construct rules and specialty of spatial data. HCR-tree was the R-tree built with HCR algorithm. To test the efficiency of HCR algorithm, it was applied not only to the data organization of static R-tree but also to the nodes splitting of dynamic R-tree. The results show that R-tree with HCR has some advantages such as higher searching efficiency, less disk accesses and so on.展开更多
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 possibil...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).展开更多
基金Supported by the National Natural Science Foundation of China(No.61872105)the Science and Technology Research Project of Heilongjiang Provincial Education Department(No.1253lz004)the Scientific Research Foundation for Returned Scholars Abroad of Heilongjiang Province of China(No.LC2018030)
文摘In view of the shortage of the spatial skyline query methods(SSQ methods) in dealing with the problem of skyline query in multidimensional space, a spatial skyline query method based on Hilbert R-tree in multidimensional space is proposed. This method takes the advantages of Hilbert R-tree which combines R-tree and Hilbert curve with high efficiency and dimensionality reduction. According to the number of query points, the proposed method in static query point environment is divided into single query point of SSQ method(SQ-HSKY algorithm) and multi-query points of SSQ method(MQP-HSKY algorithm). The SQ-HSKY method uses the spatial relationship between objects to propose pruning strategy and the skyline set in the filtering and refining process are computed. The MQP-HSKY method uses the topological relationship between data points and query points to prune non skyline points and generate the dominant decision circle to obtain the global skyline set. Theoretical study and experiments confirm the effectiveness and superiority of these methods on the skyline query.
文摘Multi-level spatial index techniques are always used in large spatial databases. After a general survey of R-tree relevant techniques, this paper presents a novel 2-level index structure, which is based on the schemas of spatial grids, Hilbert R-tree and common R-tree. This structure is named H2R-tree, and it is specifically suitable for the indexing highly skewed, distributed, and large spatial database. Algorithms and a sample are given subsequently.
文摘The characteristic of geographic information system(GIS) spatial data operation is that query is much more frequent than insertion and deletion, and a new hybrid spatial clustering method used to build R-tree for GIS spatial data was proposed in this paper. According to the aggregation of clustering method, R-tree was used to construct rules and specialty of spatial data. HCR-tree was the R-tree built with HCR algorithm. To test the efficiency of HCR algorithm, it was applied not only to the data organization of static R-tree but also to the nodes splitting of dynamic R-tree. The results show that R-tree with HCR has some advantages such as higher searching efficiency, less disk accesses and so on.
基金This work is supported by University IT Research Center ProjectKorea.
文摘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).
