Real-Time Database Systems (RTDBSs) are designed to manage the majority of current applications which manipulate a large volume of data and have a great need of real-time computation. One of the main issues in the DBMSs is to control the access to the same data items by the transactions in incompatible mode. In RTDBSs, this problem becomes more complicated since the transaction manager must not only avoid data access conflicts, but it has also to provide mechanisms that help transactions to meet their deadlines, to maximize the transactions success ratio. In this paper, we describe The SCC protocol (Speculative Concurrency Control) which is one of the first concurrency control protocol RTDBS. It is based on the transactions duplicating transactions. However, the SCC raises some problems; we propose a new extension of this protocol to solve these problems and to increase the number of transactions meeting their deadline.
Cruising for parking angers drivers, increases traffic congestion and pollution, and wastes fuel and time. This paper proposes and studies new strategies for parking guidance based on a network of intelligent agents which can helps drivers to find a parking place, before or during their travel at anytime and anywhere. With reference to the objective that is interested to bring vehicles to vacant parking place with the aim to reduce the traveling time and to ensure efficient use of available parking capacities, this study offer three services: the search for a vacant parking place, directions to that parking place and booking the place for parking. This study takes on optimal route guidance algorithm, which is simulated and analyzed by the platform MATSim transport simulation.
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