Alexandre Berred

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The management of transactions is among the main issues to tackle in many current applications such as multimedia applications or visio-conferencing. Theses applications are often distributed over several sites, they manipulate large volumes of data and their actions have temporal constraints and are causally related. Therefore, DRT-DBSs/sup 1/ are the(More)
The performance criterion generally used in real-time database systems (RTDBSs) is the transactions success ratio. In this paper, we present an analysis of firm RTDBS success ratio where we investigate the influence on the system performances of the scheduling policy, and the database workload under two main concurrency control protocols. For this purpose,(More)
The well-known and accepted criterion for measuring real-time database systems (RTDBSs) performances is to maximize the transactions success ratio. In this paper, we focus on a stochastic study of firm real-time transactions, i.e, transactions which are aborted and discarded as soon as they have missed their deadlines. The results we obtained is the(More)
In this paper, we study statistically firm real-time transactions behavior under a pessimistic and an optimistic concurrency control and scheduling protocols. Up to now, all the studies have been done on RTDBS performances by measuring the transactions success ratio (number of transactions meeting their deadlines over the total number of transactions),(More)
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