Context interchange in a client-server architecture

Many organizations today are require information from diverse information systems, and government efforts are moving towards a National Information Infrastructure for sharing information. However, the systems used by these organizations lack the capabilities to meaningfully translate information between semantically heterogeneous environments. Because the meaning of data acquired from a source environment is usually different from that needed or expected in the receiver's environment, the effectiveness of information exchange is dependent upon the system's capability for context interchange i.e., the representation, the exchange, the comparison, and the transformation of context knowledge. We show in this paper a practical means for developing context interchange capabilities in a client-server architecture, using semantic values (i.e., data and their context) as the unit of data exchange. The key components in this architecture are the context mediator server, whose job is to identify and construct the semantic values being sent, determine when the exchange is meaningful, and convert the semantic values to the form required by the client (i.e., receiver); and the data environment server, whose job is to assist in the location, access, development and maintenance of the context knowledge for all clients and servers.