EPFL doctorate Award 2007 - Cudré-Mauroux Philippe

"For his groundbreaking work on emergent semantics in peer-to-peer data management systems"

Emergent semantics: rethinking interoperability for large scale decentralized information systems.

In the past, the problem of interoperability in information systems was solved by means of centralization, both at a system and at a logical level. We argue that traditional top-down integration techniques are inapplicable to large-scale, decentralized information systems and propose a new integration architecture based on peer-to-peer schema mappings and dynamic self-organization. Throughout this thesis, we model semantics as bottom-up and dynamic agreements among heterogeneous parties. We consider both the representation of semantics and the discovery of the interpretation of symbols as the result of a self-organizing process performed by distributed agents whose utility functions depend on the proper interpretation of the symbols. We introduce new metrics to capture the semantic mismatch between pairs of acquainted information systems. We describe a totally decentralized message passing scheme based on transitive closures of mappings to efficiently evaluate our metrics. We also show how to take advantage of our metrics to gradually alleviate mapping inconsistencies, and to quantify through a graph-theoretic analysis the quality of the global agreement that can be achieved in that way. Finally, we describe two systems illustrating the practical applicability of our ideas.

Also distinguished by the mention EPFL-PRESS delivered by the PPUR.