1. ©2002, Karl Aberer, EPFL, Laboratoire de systèmes d'informations répartis Semantic Gossiping Karl Aberer, EPFL karl.aberer@epfl.ch Distributed Information Systems Laboratory lsirwww.epfl.ch NSF-EU Workshop on Database and Information Systems Research for Semantic Web and Applications April 3-5, Amicalola Falls

2. ©2002, Karl Aberer, EPFL, Laboratoire de systèmes d'informations répartis Peer-to-Peer Networks (Gnutella) Content: mainly music files Schema:file name Query: keywords

3. ©2002, Karl Aberer, EPFL, Laboratoire de systèmes d'informations répartis Gnutella Network Structure [Jovanovic 01]

4. ©2002, Karl Aberer, EPFL, Laboratoire de systèmes d'informations répartis Semantics as Network Phenomenon Generate semantics locally –Communication among nodes –Decentralization, scalability Study evolution of semantics globally –Emergent properties of (social) networks Study the problem for well-accepted applications using standard platforms –Experimental approach

5. ©2002, Karl Aberer, EPFL, Laboratoire de systèmes d'informations répartis Proposal: Semantic Gossiping Content: media, publications, scientific data Schema: XML DTD or schema Query: XPath or XQuery Network: broadcast of search requests (gossip) "From Gnutella to Semantic Gnutella"

6. ©2002, Karl Aberer, EPFL, Laboratoire de systèmes d'informations répartis Scenario Semantic Gossiping: Local View Q1= $s/Title FOR $s IN /Song WHERE $s/Size<1000000 Q2= $s/Title FOR $s IN T12 WHERE $s/Size<1000000 21st century schizoid man King Crimson 23456789 Schema 1 21st century schizoid man King Crimson 23456789 Schema 2 T12= $t/Name $t/Author $t/Bytes FOR $t IN /Title

7. ©2002, Karl Aberer, EPFL, Laboratoire de systèmes d'informations répartis Scenario Semantic Gossiping: Global View

8. ©2002, Karl Aberer, EPFL, Laboratoire de systèmes d'informations répartis Questions Nature of graphs ? –Hypothesis: small world Distribution of schemas ? –Hypothesis: power-law Performance of Search ? –Hypothesis: Intra-cluster good: scalable indexing Inter-cluster fair: gossiping

9. ©2002, Karl Aberer, EPFL, Laboratoire de systèmes d'informations répartis More Information on P2P: www.p-grid.org