User-oriented cache deletion algorithm in a delayed update-tolerant web cache server for supporting a non-formal education

In developing countries, it is often difficult to use web content for e-learning because Internet accessing is unavailable or limited. To support education in such a situation, the authors previously proposed a system that uses a delayed update-tolerant web cache server and a wireless LAN. This system stores e-learning webpages requested by free school children in a cache memory, which is then carried to the free school so that the children can access the webpages in an off-line environment. The present paper proposes a cache deletion algorithm that reflects children’s requests for content retention in the cache server. It is called a user-oriented least recently used (LRU) algorithm. We have developed an experimental system that implemented this algorithm and carried out a learning experiment under conditions that simulated actual usage. We compared the proposed algorithm with existing cache deletion algorithms, including the least recently used (LRU), the least frequently used (LFU) and the least frequently recently used (LFRU) algorithms, in terms of the frequently accessed leaning cache retention rate.