Caching Invalidation Strategies for Supporting ´Weak´ Location Dependent Queries

Caching technique has been widely used to accelerate data access for Location Dependent Information Services (LDISs) in mobile environments. Many existing LDISs focuse primarily on finding the nearest object. However, for some applications, closest location information is not strictly necessary. In this paper, we study caching invalidation strategies for ´weak´ location dependent queries which require only loosen location constraints. First, we introduce a weak location dependent caching scheme to handle such queries. Then, we propose an efficient strategy based on weak valid scope to facilitate cache invalidation. Finally, we evaluate our strategies by simulations. Experimental results show that better cache hit ratios and lower communication cost can be achieved using this scheme..