Hei-Wing Leung

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In this paper, we propose a cache invalidation scheme called Invalidation by Absolute Validity Interval (IAVI) for mobile computing systems. In IAVI, we define an absolute validity interval (AVI), for each data item based on its dynamic property such as the update interval. A mobile client can verify the validity of a cached item by comparing the last(More)
In this paper, we study the data dissemination problem in time-constrained mobile computing systems (TCMCS) in which maximizing data currency (minimizing staleness) and meeting transaction deadlines are of equal importance as providing consistent data items to transactions. We first investigate what are the performance problems of the multi-version data(More)
Although data broadcast has been shown to be an efficient method for disseminating data items in mobile computing systems, the issue on how to ensure consistency and currency of data items provided to mobile transactions (MT), which are generated by mobile clients, has not been examined adequately. While data items are being broadcast, update transactions(More)
In a mobile computing system, caching data items at the mobile clients is important to reduce the data access delay in a unreliable and low bandwidth mobile network. However, efficient methods must be used to ensure the coherence between the cached items and the data items at the database server. In this paper, by exploring the real-time properties of the(More)
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