Performance Analysis of Algorithms for Supporting Disconnected Write Operations in Wireless Web Environments

PERFORMANCE ANALYSIS OF ALGORITHMS FOR SUPPORTING DISCONNECTED WRITE OPERATIONS IN WIRELESS WEB ENVIRONMENTS Ngoc Anh Phan M.S. thesis directed by Dr. Ing-Ray Chen A mobile user may voluntarily disconnect itself from the web server to save battery life and also to avoid the high communication price. To allow web pages to be updated while the mobile user is disconnected from the web server, updates can be staged in the mobile unit and propagated back to the web server upon reconnection. In this thesis, we investigate methods for supporting disconnected write operations and develop a performance model which helps identify the optimal length of the disconnection period under which the cost of update propagation is minimized. We validate the analytic model with simulation in the thesis. We also show how the result can be applied to real-time web applications with a deadline requirement to propagate updates of web pages. The analysis result is particularly applicable to web applications which allow wireless mobile users to modify web contents while on the go. The algorithms that we have developed can be generally applied to other data items such as files and databases. Index Terms — Wireless mobile systems, web access, disconnected operations, performance analysis, coherency interval, hoarding, reintegration.