Browsing by Subject "Active Databases"

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    Automated construction of fuzzy event sets and its application to active databases
    (IEEE, 2001) Saygin, Y.; Ulusoy, Özgür
    Fuzzy sets and fuzzy logic research aims to bridge the gap between the crisp world of math and the real world. Fuzzy set theory was applied to many different areas, from control to databases. Sometimes the number of events in an event-driven system may become very high and unmanageable. Therefore, it is very useful to organize the events into fuzzy event sets also introducing the benefits of the fuzzy set theory. All the events that have occurred in a system can be stored in event histories which contain precious hidden information. In this paper, we propose a method for automated construction of fuzzy event sets out of event histories via data mining techniques. The useful information hidden in the event history is extracted into a matrix called sequential proximity matrix. This matrix shows the proximities of events and it is used for fuzzy rule execution via similarity based event detection and construction of fuzzy event sets. Our application platform is active databases. We describe how fuzzy event sets can be exploited for similarity based event detection and fuzzy rule execution in active database systems.
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    Concurrent rule execution in active databases
    (Elsevier, 1998) Saygın, Y.; Ulusoy, Özgür; Chakravarthy, S.
    An active DBMS is expected to support concurrent as well as sequential rule execution in an efficient manner. Nested transaction model is a suitable tool to implement rule execution as it can handle nested rule firing and concurrent rule execution well. In this paper, we describe a concurrent rule execution model based on parallel nested transactions. We discuss implementation details of how the flat transaction model of OpenOODB has been extended by using Solaris threads in order to SUppOrt COnCUrrent eXeCUtiOU of rUkS. C
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    Implementation of parallel nested transactions for nested rule execution in active databases
    (1996) Saygın, Yücel
    (Jonventional, passive datal)ases, ex('cute transcictions or queries in response to the requests from a user or an application program. In contrcist, an Active Database Management System (ADI3MS) allows users to specify actions to be executed when some specific evcMits are signaled. ADBMSs ¿ichieve tliis feciture by mecins of rules. Execution of ruh's is an important part of an ADBMS which may affect the overall performanc'e of the system. Nested transactions are proposed as a rule execution model for ADBMSs. The nested trcinsciction model, in contrast to flat transactions, allows transactions to be started inside some other trcinsactions forming a transaction hierarchy. In this thesis, implementation issues of pcirallel nested transactions, wluM’e all the transactions in the hierarchy may run in pcirallel, aix' discussed for parallel rule execution in ADBMSs. Implementation of nested transactions ha.s I^een performed by extending the flat trcuisaction semantics of OpenOODB using Solaris threads. A formal specification of the proposed (xxec.ution model using ACTA framework is also provided.