The Department of Computer Science at the University of Cyprus cordially invites you to the Colloquium entitled:

Adaptive Resource Location and Query Processing for Peer-to-Peer Networks


Speaker: Dr. Dimitrios Tsoumakos
Affiliation: NTUA, Greece and University of Cyprus, Cyprus
Category: Colloquium
Location: Room 148, Faculty of Pure and Applied Sciences (FST-01), 1 University Avenue, 2109 Nicosia, Cyprus (directions)
Date: Wednesday, November 4th, 2009
Time: 15:00-16:00 EET
Host: Demetris Zeinalipour (dzeina AT

Peer-to-Peer (P2P) computing has gained a lot of attention from both the scientific and the large Internet user community. Popular applications utilizing this new technology offer many attractive features to a growing number of users while taking up a large amount of everyday network traffic. This talk presents bandwidth-efficient and adaptive algorithms to facilitate data location and processing for massive data management applications that operate on P2P overlays. The basis of these schemes is their ability to learn from past interactions, increasing their performance with time. In the first part of the talk, previous work in efficient content location and distribution for Unstructured Peer-to-Peer overlays is described. The Adaptive Probabilistic Search (APS) scheme utilizes directed walkers to forward queries on a hop-by-hop basis. Peers store success probabilities for each of their neighbors in order to efficiently route towards object holders. In the GrouPeer project, we apply many of these techniques in order to identify and group peers with similar schemas in an interconnected network of autonomous databases. In the second part of the talk I will present some of my current work which focuses on indexing methods for data and query-intensive applications over P2P overlays. HiPPIS and PASSION are systems that utilize adaptive algorithms that automatically adjust the level of indexing (for hierarchically organized data or ranges respectively) according to the granularity of the incoming queries, without assuming any prior knowledge of the workload. Brown Dwarf is a complete system for distributing and querying data-cubes w.r.t. load and network/node failures.

Short Bio:
Dimitrios Tsoumakos is a visiting lecturer at the Computer Science Department of UCY. He received his Diploma in Electrical and Computer Engineering from NTUA in 1999, joined the graduate program in Computer Sciences at the University of Maryland in 2000, where he received his M.Sc. (2002) and Ph.D. (2006). He has been collaborating as a senior researcher with the Computing Systems Laboratory in the Department of Electrical and Computer Engineering of the National Technical University of Athens (NTUA) since 2006.

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Sponsor: The CS Colloquium Series is supported by a generous donation from Microsoft