Title:
A SpatioTemporal Placement Model for Caching Location Dependent Queries
A SpatioTemporal Placement Model for Caching Location Dependent Queries
Author(s)
Murugappan, Anand
Liu, Ling
Liu, Ling
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Abstract
Client side caching of location dependent queries is
an important technique for improving performance of location-based
services. Most of the existing research in this area has
focused on cache replacement and invalidation through incorporating
some aspects of the spatial and temporal semantics
embedded in the location queries, while assuming an ad hoc
cache placement. Very few have studied the impact of spatial and
temporal validity semantics and the motion behavior of mobile
clients on the effectiveness of cache placement and ultimately
the performance of the client cache. This paper proposes an
adaptive spatio-temporal placement scheme for caching location
dependent queries. The cache placement decision is made
according to the potential cache benefit of the query results
based on the spatio-temporal properties of query results and
the movement patterns of the mobile client, aiming at increasing
the cache hit ratio. We introduce the concept of ‘Overlapping
Cache Benefit’ as a measure of the hit rate of a cached item,
and present three spatio-temporal cache placement schemes,
which provide a step-by-step in-depth analysis of various factors
that may affect the performance of a client cache in mobile
environments. We implemented the spatio-temporal placement
model in the first prototype of the MOBICACHE system. Our
experimental evaluation shows that the spatial locality and the
movement patterns of mobile clients are critical factors that
impact the effectiveness of cache placement and the performance
of client cache, and the proposed adaptive spatio-temporal cache
placement approach yields higher hit ratio and better response
time compared to existing mobile cache solutions.
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Date Issued
2007
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Text
Resource Subtype
Technical Report