| Summary: | 碩士 === 國立交通大學 === 資訊工程系 === 89 === Wireless Application Protocol (WAP) was developed to support efficient wireless data access. Since data transmission capacity of wireless link is limited, a caching model was proposed for WAP to reduce the data access time. Many WAP applications also exhibit temporal locality for data access, and the cache in a WAP handset can effectively reduce the data access time by exploiting this property. This thesis investigates the cache performance for WAP handheld devices. We consider the least recently used replacement policy and two strongly consistent data access algorithms called poll-each-read and callback. In poll-each-read, whenever a data access occurs, the client always asks the server whether the cached entry in the client is valid or not. In callback, the server always invalidates the cached entry in the client whenever a data updates occurs. We propose analytic and simulation model to investigate the effective hit ratio of data access. Our study indicates that callback may significantly outperform poll-each-read. We also report how the data access rate and the data update distribution affect the cache performance in a WAP handheld device.
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