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A class algebra has been used to model the query and data manipulation language for a prototype object-oriented database system which is being implemented for the WorldWide Web [7]. The Prolog prototype (i.e. operational semantics, if you will) is located at The class algebra includes a Boolean algebra for class union, intersection, and complement (i.e.(More)
Many asynchronous distributed atomic commit protocols use a coordinator, either an application server or an elected database server, to handle the progress of a transaction. When the coordinator fails or the network becomes partitioned, the transaction may block or may suffer from a split brain syndrome. In this paper we propose a decentralized,(More)
We propose a trust framework model for an educational cloud which is designed to overcome inequalities of M-shaped incomes by simplifying contract-based sharing of resources among multiple schools. We use class algebra, which is similar to SROIQ(D) description logic, as the access control policy language. Benefiting from the high expressivity of class(More)