Querying fuzzy spatiotemporal data using XQuery

摘要

How to accurately handle querying criteria based on user's preferences has become a key technology for querying fuzzy spatiotemporal data, typically collected by modern monitoring devices such as GPS receivers and sensors. 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 approach for querying fuzzy spatiotemporal data using XQuery. On the basis of its architecture, we make extensions to XQuery language. The extensions consist of the new xs: truth data type intended to represent gradual truth degrees, and the new Val element and the new Poss attribute to handle satisfaction degrees. Furthermore, fuzzy spatiotemporal linguistic terms are extended to declare fuzzy terms and use them in querying expressions. Additionally, FLWOR are extended to support fuzzy spatiotemporal queries. After extensions of XQuery on fuzzy spatiotemporal data, we present real case querying examples, discuss crucial details of their processing, and perform evaluations of each querying example. Finally, the comparative study demonstrates the advantages of our approach.