Data Organization Issues for Location-Dependent Queries in Mobile Computing
We consider queries which originate from a mobile unit and whose result depends on the location of the user who initiates the query. Example of such a query is How many people are living in the region I am currently in?” We execute such queries based on location-dependent data involved in their processing. We build concept hierarchies based on the location data. These hierarchies define mapping among different granularities of locations. One such hierarchy is to generate domain knowledge about the cities that belong to a state. The hierarchies are used as distributed directories to assist in finding the database or relation that contains the values of the location-dependent attribute in a particular location. We extend concept hierarchies to include spatial indexes on the location-dependent attributes. Finally, we discuss how to partition and replicate relations based on the location to process the queries efficiently. We briefly discuss the implementation issues.
KeywordsGlobal Position System Query Processing Location Attribute Mobile Computing Mobile Host
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