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Making a database system active entails developing an expressive event specification language with well-defined semantics, algorithms for the detection of composite events, and an architecture for an event detector along with its implementation. Thii paper presents the semantics of composite events using the notion of a global event history (or a global(More)
This paper proposes a new approach for supporting reactive capability in an object-oriented database. We introduce an <italic>event interface</italic>, which extends the conventional object semantics to include the role of an event generator. This interface provides a basis for the specification of events spanning sets of objects, possibly from different(More)
The effect of fluoride ion concentration on the corrosion behavior of Ti and Ti6Al4V implant alloys, when coupled with either metal/ceramic or all-ceramic superstructure, was examined by different electrochemical methods in artificial saliva solutions. It was concluded that increased fluoride concentration leads to a decrease in the corrosion resistance of(More)
This paper presents some of the advantages accrued from adopting an object-oriented (OO) data model versus the relational data model when representing and managing a Vector Product Format (VPF) database, specifically the Digital Nautical Chart (DNC) for Norfolk Harbor, Virginia. An OO-DNC prototype viewer capable of importing, displaying and editing DNC(More)
Use of databases for non-traditional applications has prompted the development of new transaction models whose semantics vary from the traditional model, as well as from each other. The implementation details of most of the proposed models have been sketchy at best. Furthermore, current architectures of most DBMSs do not lend themselves to supporting more(More)
This paper presents an approach for supporting reactive capability in an objectoriented GIS database, through the use of an event interface comprising an event generator and rule objects. This interface supports specification of events spanning sets of geographic-feature objects, and detection of primitive and complex events. Rules can be specified to apply(More)
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