FSPTwigFast: Holistic twig query on fuzzy spatiotemporal XML data

With spatiotemporal applications increasing, a large amount of spatiotemporal data emerges. Because temporal and spatial attributes are often vague, research on fuzzy spatiotemporal data, especially querying fuzzy spatiotemporal data, has attracted a lot of attention. However, although fuzzy logic is incorporated in querying fuzzy spatiotemporal data and querying fuzzy data in XML, relatively little work has been carried out in querying fuzzy spatiotemporal data in XML. In this paper, we propose an algorithm, called FSPTwigFast, to match fuzzy spatiotemporal XML twig pattern. We represent fuzzy spatiotemporal data by adding temporal and spatial attributes associating with fuzziness in crisp data. We extend Dewey code to mark fuzzy spatiotemporal data for special process and determine structure relationship of fuzzy spatiotemporal nodes in XML documents. Our technique uses streams to store leaf nodes in XML document corresponding to leaf query nodes, which are filtered to delete unmatched nodes. After filtering, output lists are built for every matched leaf node. Finally, the experimental results demonstrate the performance advantages of our approach.