SEMALRU: An Implementation of modified web cache replacement algorithm

Abstract

The increasing demand for World Wide Web (WWW) services has made document caching a necessity to decrease download times and reduce Internet traffic. This work aims at implementing SEMALRU-a semantic and least recently used Web cache replacement policy. The basic LRU replacement policy is augmented with semantic content of Web pages to improve the efficiency of the replacement algorithms in terms of hit rate and byte hit rate and to minimize the number of replacements made in cache. There are many well-known cache replacement policies based on size, recency, and frequency. This new improvised replacement policy attempts to implement cache replacement based on two parameters namely the semantics of the contents of Web pages and the time of last access of the document. SEMALRU evicts documents that are less related to an incoming document or least recently used document which needs to be stored in the cache. This makes sure that only related documents are stored in the cache; hence the contents of the cache represent the documents of interest to the user and then ranked by recency. This policy tunes the performance of the existing replacement algorithms through analyzing the semantic content of the document and the recency of the document. A detailed algorithm to identify unrelated documents and documents that are least recently used has been devised. The policy was tested in a simulated environment with the related and unrelated set of user access pattern. The parameters pertinent to cache replacement algorithms are computed and the results showing the improvement in the efficiency of the algorithm are furnished.