With the increase in the number of mobile users, the need for new type of services and applications is also on the rise. Particularly, a growing area of interest is to provide location dependent services to the mobile users. In this paper, we introduce an efficient approach for processing the location dependent continuous queries using mobile agents and proactive caching. We investigate a common scenario in which both the querying unit and the object being queried are capable of movement. Since continuous queries are dealt with, we propose a heuristic approach from the moving behavior of the mobile unit such as location, direction and speed in a 2-dimensional space. Mobile agents are deployed in query processing to minimize the bandwidth utilization and to manage the frequent handoffs and disconnections. Moreover, it helps in concurrent evaluation of queries by a number of mobile units and reduces the latency of individual steps required to establish connection before data transfer can be performed and in continuing the database processes in the absence of network connection. This system also provides an efficient caching mechanism called Proactive caching that helps in minimizing the data traffic between the mobile unit and the base station and also the cached data is possible of being used for different types of location dependent queries unlike prior caching techniques where the cached data are semantically dependent on the query type. The cache replacement policy used in this work helps in purging the cache when the data available in the cache is no longer valid.
展开▼
