Pruning Strategies to Refine Resource List for NN Queries in Location based Services

Location based services suggest resources (Fuel station, Restaurant, ATM stations etc.) to the users based on the query location during mobility. In case of nearest neighbor query, the list of resources represents those that are within a specified range from the query location. The query may be executed either in Euclidean space or based on road network. It may happen that the list has both usable and unusable number of resources. Also in case of road network based query execution, if there exist some resources that are not available in the road based resource database, they may not be added to the resource list. It becomes essential to suggest the most appropriate resources and the suggestion process requires certain pruning strategies to be applied over the query process. This paper focuses on considering travel path and direction of resource related to query point for refining the list of resources. In this regard, we suggest the use of polar tree combined with the travel direction to yield a refined list.