Approximate Answers in Location-Dependent Query Processing

Location-dependent applications are becoming more and more popular in the mobile computing environment. To improve system performance and deal with disconnection, some criteria are relaxed to enhance availability. A location query processing model using generalized databases is proposed. When primitive databases accessed are either undesirable or unavailable, this model can return approximate answers using generalized databases and concept hierarchies stored at mobile units. This model provides a more optimal use of data during periods of disconnection and enables efficient utilization of low bandwidth and restricted memory size. This model is able to provide varying levels of approximate answers. Some cost-benefit analyses involving transmission and query processing costs are also discussed.