Many application areas require the integration of heterogeneousinformation sources into a coherent distributed information system. Withsuch systems, users frequently need not only be able to accessinformation, but they also have to be notified automatically when newinformation that is relevant to their work becomes available. Forexample, an our environmental systems project, a civil servant needs tobe informed when a measured air quality parameter exceeds a certainthreshhold. Detection of such a critical situation requires subsequentmonitoring of several data sources (e.g., a database recordingmeasurement values and a database with limit values). The paper presentsan approach for such situation monitoring which is based on CORBA, forthe technical integration of heterogeneous systems and on activeDBMS-style ECA-rules. In particular, it discusses how ECA-rules can beadopted in a CORBA environment, and describes a CORBA-based system forsituation monitoring. The major implementation issues addressed areevent detection within autonomous component systems and detection ofcomplex distributed situations
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