In 2001-2, we developed the Mobiscope service discovery system for mobile network resources. Mobiscope is a discovery service where clients submit long-running queries to continually find sets of moving network resources within a specified area. As in moving object databases (MODBMSs), moving resources advertise their positions as functions over time. When Mobiscope receives a query, it runs the query statically against advertisements (ads) that are currently cached by Mobiscope, and then continuously over ads that Mobiscope receives subsequently. For scalability, Mobiscope distributes the workload to multiple nodes by spatial coordinates. Application-level routing protocols based on geography ensure that all queries find all matching resources on any node without significant processing overhead. Simulation results indicate that Mobiscope scales well, even under workloads that stress Mobiscope's distribution model.
The current Mobiscope design only allows queries that find moving objects within a given region. We are currently extending our design to support temporal operators in the Mobiscope query language in order to support more complex queries.
1IBM T.J. Watson Research Center
2IBM T.J. Watson Research Center