Changes, Consistency and Configuration in Heterogeneous, Distributed Systems

The objective of the effort was to develop a unifying framework for change management and automatic change notification suitable for diverse heterogeneous information sources, and to demonstrate that the framework can be realized in a flexible, efficient, and scalable manner. Our results are as follows 1 We designed and implemented a model for change management in heterogeneous information sources. The model, called DOEM for Delta-OEM is based on a simple semistructured object model called OEM developed within the companion DARPA funded Tsimmis project. 2 We developed sophisticated algorithms for detecting changes in semistructured data. Historical information produced by our change detection algorithms is stored in our Lore system Lightweight Object Repository. Lore is a DBMS suitable for DOEM and OEM data, and was developed in part within the C3 project. 3 We designed and implemented a query language, called Chorel for Change-Lorel, which is based on Lorel, the query language of Lore. 4 Using our DOEM model, change detection algorithms, and Chorel query language as basic building blocks, we designed and implemented a Query Subscription Service QSS.