¡@

Many recent studies in the field of data transmission have considered locationbased services. Prefetching and caching are exemplary techniques for data transmission, and offer advantages in user-centric services in location-dependent data environments. However, in mobile environments, prefetching and caching inevitably require frequent uplink requests because the data that is needed in the clients¡¦ current location has to be transmitted from a server. To overcome this drawback, this paper presents a semantic prefetching scheme, with descriptions and cache replacement policies, based on range query processing algorithms. To decrease frequent uplink requests, when a client enters a new service area, that is, a semantic prefetching area, our scheme fetches the necessary descriptions and data from the server in advance. The client maintains the descriptions in its own cache using proposed semantic least recently used, semantic least frequently used, and preference priority replacement policies. Range queries can get their results from the cache, with only a few requests to the server, regardless of mobility and query patterns. Experimental results show that our semantic prefetching scheme is more efficient than the existing scheme in terms of cache efficiency and data accessibility.

Keywords: semantic prefetching, range query, cache replacement, locality, preference, query saving ratio, location-based services

Retrieve PDF document (200811_12.pdf)

Received January 30, 2007; revised June 11, 2007; accepted October 18, 2007.
Communicated by Chung-Ta King.
^* Sang-Won Kang, Jongwan Kim, SeokJin Im, HaRim Jung, and Chong-Sun Hwang, ¡§Cache Strategies for Semantic Prefetching Data,¡¨ in Proceedings of the Seventh International Conference on Web-Age Information Management Workshops (WAIMW' 06), 2006, p. 7.
^* This work was supported by the Second Brain Korea 21 Project.
⁺ Corresponding author