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DTSTART:20161030T030000
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
RDATE:20171029T030000
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DTSTART:20170326T020000
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UID:calendar.12405.field_data.0@www.ugov-ricerca.uniroma1.it
DTSTAMP:20260407T072301Z
CREATED:20170518T080315Z
DESCRIPTION: The study of online algorithms and competitive analysis provid
 e a solid foundation for studying the quality of irrevocable decision maki
 ng when the data arrives in an online manner. While in some scenarios the 
 decisions are indeed irrevocable\, there are many practical situations whe
 n changing a previous decision is not impossible\, but simply expensive.In
  this work we formalize this notion and introduce the consistent k-cluster
 ing problem. With points arriving online\, the goal is to maintain a const
 ant approximate solution\, while minimizing the number of reclusterings ne
 cessary. We prove a lower bound\, showing that Ω(k log n) changes are nece
 ssary in the worst case\, for a wide range of objective functions. On the 
 positive side\, we give an algorithm that needs only O(k^2 log^4 n) change
 s to maintain a constant competitive solution. This is an exponential impr
 ovement on the naive solution of reclustering at every time step. Finally\
 , we show experimentally that our approach performs much better than the t
 heoretical bound\, with the number of changes growing approximately as O(l
 og n). Joint work with Sergei Vassilvitskii. Bio:Silvio is a Research Scie
 ntist at Google Research Europe since April 2017. Before he was in the NY 
 Algorithm group at Google New York from January 2011 to March 2017. He rec
 eived his PhD from Sapienza University of Rome under the supervision of Al
 essandro Panconesi. During his PhD he interned twice at Google and once at
  Yahoo! Research.His research interests are in the areas of algorithms\, m
 achine learning and information retrieval. 
DTSTART;TZID=Europe/Paris:20170524T150000
DTEND;TZID=Europe/Paris:20170524T150000
LAST-MODIFIED:20190805T155053Z
LOCATION:Aula Magna - DIAG
SUMMARY:Consistent K-Clustering - Silvio Lattanzi (Google Research)\, Wedne
 sday\, May 24th\, 15:00  - Silvio Lattanzi (Google Research)
URL;TYPE=URI:http://www.ugov-ricerca.uniroma1.it/node/12405
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