infonet-economy

The messenger paradigm advocates the exchange of programs called messengers between communicating hosts instead of messages. Each host contains a messenger execution environment called messenger platform. Messengers are expressed in a language understood by all the platforms. A distributed messenger environment is a collection of messenger platforms linked through an unreliable network offering only a datagram service. Provision of coordination services in such an environment has to be handled in a new way since threads of controls are mobile (messengers move from host to host). The classical client/server paradigm based on a data exchange mechanism is not suitable for a messenger environment. In this paper we discuss how communication services might be provided in messenger environments using as an example the distributed semaphore service in the MØ distributed messenger environment. A distributed semaphore allows messengers executing on different hosts to synchronize their execution independently of their physical location.

In this paper, we describe a technique for integrating heterogeneous information systems using concept bases. A concept base is build on top of each system to integrate, in order to semantically enrich its description. Each concept is described at three different levels: terminological definition, formal characterization, and representation in the underlying system. The different concept bases are then used to compare the concepts represented in the different systems and to establish correspondences between them in order to facilitate communication, cooperation, or integration. Our approach relies on results of the ConcepTerm project, dedicated to the study of concept dictionary building methodology and process. We also show that the building of a concept base can benefit database design and high-level interface definitions.