关键词: 移动计算, 移动支持站点, 语义缓存, 失效报告, 粒度细化

Abstract:

The traditional algorithms of semantic cache consistency maintenance are of enormous data communication cost and space complexity of invalidation report. However,most of the current researches mainly focus on the client's algorithms and are unable to solve the above-mentioned problems radically. In this paper,a novel method of semantic cache consistency maintenance with a three-layer cache structure is proposed,which uses the mobile support station ( MSS) to store mobile client's semantic cache items. Then,the corresponding index table is presented and an invalidation report is created based on the bit sequence to further shorten the report length. Finally,the updating sequence is stored in a queue and is used to refine the updated granularity and simplify the consistency maintenance from clients,thus saving the network bandwidth and supporting the cache consistency maintenance in the condition of frequent network disconnection. Simulated results show that the proposed algorithm remarkably reduces the invalidation report size and saves the data communication cost for consistency maintenance.

Key words: mobile computing, mobile support station, semantic cache, invalidation report, granularity refining