Selecting stars: fast and accurate computation of representative skylines for finding interesting records under multiple criteria.

Day - Time: 11 October 2012, h.11:00
Place: Area della Ricerca CNR di Pisa - Room: C-29
  • Matteo Magnani (Data Intensive Systems group, Dept. of Computer Science, Aarhus University, Denmark)

Fosca Giannotti


Which basketball player has been the Most Valuable Player in the last NBA season? Which materials should we use to build a product in a short time, that is cheap but is still appreciated by our customers? Which hotels are cheap but also not too far from the beach? These are all examples of queries involving multiple criteria, e.g., (1) cost and (2) distance to the beach. Only if the importance of each criterion is known (how far am I willing to walk for each saved euro?) we can compute a ranking of the best records (hotels). Otherwise, the "skyline" (aka Pareto front) consists of all the best records for all possible weighing of the criteria, thereby giving an overview over all the best options in the data.

In this talk I will introduce the skyline database operator for the selection of records under multiple criteria. Then I will discuss two important limitations of this operator: skyline queries can produce a very large result and require high computation time. I will thus present the main status of the research on the fast selection of "stars", i.e., a small set of records providing a good representation of the whole skyline.

Biography of the speaker: Matteo Magnani graduated in Computer Science at the University of Bologna in 2002 (110/110 with mention). He studied at the University of Marne la Vallée (undergraduate level) and the Imperial College London (postgraduate research level). In 2006 he obtained a PhD in Computer Science (Bologna) where in 2011 he also graduated in Violin (110/110 with mention). He has received a Rotary Prize for the best student of the Science Faculty (UniBO), a Best Paper Award at ASONAM 2011, a Funniest Presentation award at SBP 2010, the French qualification for Maître de Conférence positions, the Italian "idoneità " for CNR researcher positions and his mother is very proud of him (or at least this is what she officially says). Until May 2012 he was a researcher (RTD) at the Dept. of Computer Science, University of Bologna and he currently holds a position at research assistant professor level at the Data Intensive Systems group, Dept. of Computer Science, Aarhus University, Denmark.

His main research interests span Database and Information Management systems, specifically uncertain information management and multidimensional database queries, and Social Computing. He has written around 1.5 Kg of papers on these topics (when printed on heavy A4 size sheets). He is currently the joint coordinator of the #sigsna research group on social network analysis, and has successfully attracted funding from Working Capital (Telecom Italia), PRIN and FIRB (MIUR - Italian Ministry for education, University and Research) schemes.