A Query Processing Model for Mobile Computing using Concept Hierarchies and Summary Databases
Sanjay Madria, Mukesh Mohania, John F. Roddick · 2007
We present a query-processing model for mobile computing using summary databases (database stored in some predefined condensed form). We use concept hierarchies to generate summary databases from the main database in various ways. Traditional database management systems are correct in that they are able to provide answers to queries that are both sound and complete with respect to the source data. In a mobile environment, it may be advantageous to relax one or other of these criteria to enhance availability through the use of summary databases. This would provide a more optimal use of data during periods of disconnection and to enable efficient utilization of low bandwidth and restricted memory size. The model for query processing proposed uses concept hierarchies and summary databases at run time to return approximate queries when access to the main database is either undesirable or unavailable. We present a model that is able to provide varying levels of approximate answer to queries that occur at a mobile host using the summary database stored either locally at mobile host (MH) or remotely at mobile service stations (MSS). The paper also discusses some cost-benefit analyses involving storage, transmission and query processing costs. Keywords -- query processing, mobile computing, summary database, concept hierarchy, sound, complete. 1