Abstract-The transformation of existing local databases to meet diverse application needs at the global level is performed through a four-layered procedure that stresses total schema integration and virtual integration of local databases. The proposed methodology covers both schema integration and database integration, and uses a four-layered schema architecture (local schemata, local object schemata, global shema, and global view schemata) with each layer presenting an integrated view of the concepts that characterize the layer below. Mechanisms for accomplishing this objective are presented in theoretical terms, along with a running example. Object equivalence classes, property equivalence classes, and other related concepts are discussed in the context of logical integration of heterogeneous schemata, while object instance equivalence classes and property instance equivalence classes, and other related concepts are discussed for data integration purposes. The proposed methodology resolves naming conflicts, scaling conflicts, type conflicts, and level of abstraction, and other types of conflicts during schema integration, and data inconsistencies during data integration.

No abstract

This paper chiefly discusses the implementation of Sowa's ConceptualGraph notation using a frame-like data structure. Conceptual graphs serve as the basis for knowledge representation in our two systems, LEAD (Learning Expert system for Agricultural Domain) and XLAR (Universal Learning ARchitecture). The importance of conceptual graphs in knowledge representation is also briefly accounted for. Rationale for choosing frames for conceptual graph implementation is presented. Comparison of this implementation with other extant implementations is made.

No abstract

No abstract