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Spatial Approximate String Search. Abstract This work deals with the approximate string search in large spatial databases. Specifically, we investigate.

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Presentation on theme: "Spatial Approximate String Search. Abstract This work deals with the approximate string search in large spatial databases. Specifically, we investigate."— Presentation transcript:

1 Spatial Approximate String Search

2 Abstract This work deals with the approximate string search in large spatial databases. Specifically, we investigate range queries augmented with a string similarity search predicate in both euclidean space and road networks. We dub this query the spatial approximate string (SAS) query. In euclidean space, we propose an approximate solution, the MHR-tree, which embeds min-wise signatures into an R-tree. The min-wise signature for an index node u keeps a concise representation of the union of q-grams from strings under the subtree of u. We analyze the pruning functionality of such signatures based on the set resemblance between the query string and the q-grams from the subtrees of index nodes.

3 Abstract con… We also discuss how to estimate the selectivity of a SAS query in euclidean space, for which we present a novel adaptive algorithm to find balanced partitions using both the spatial and string information stored in the tree. For queries on road networks, we propose a novel exact method, RSASSOL, which significantly outperforms the baseline algorithm in practice. The RSASSOL combines the q-gram-based inverted lists and the reference nodes based pruning. Extensive experiments on large real data sets demonstrate the efficiency and effectiveness of our approaches.

4 Existing System keyword search over a large amount of data is an important operation in a wide range of domains. Felipe et al. have recently extended its study to spatial databases [17], where keyword search becomes a fundamental building block for an increasing number of real-world applications, and proposed the IR 2 -Tree. A main limitation of the IR 2 -Tree is that it only supports exact keyword search. In practice, keyword search for retrieving approx­imate string matches is required [3], [9], [11], [27], [28], [30], [36], [43].

5 Archirtecture Diagram

6 System Specification HARDWARE REQUIREMENTS Processor : intel Pentium IV Ram : 512 MB Hard Disk : 80 GB HDD SOFTWARE REQUIREMENTS Operating System : windows XP / Windows 7 FrontEnd : Java BackEnd : MySQL 5

7 CONCLUSION This paper presents a comprehensive study for spatial approximate string queries in both the euclidean space and road networks. We use the edit distance as the similarity measurement for the string predicate and focus on the range queries as the spatial predicate. We also address the problem of query selectivity estimation for queries in the euclidean space. Future work includes examining spatial approximate substring queries, designing methods that are more update friendly, and solving the selectivity estimation problem for RSAS queries.

8 THANK YOU


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