Loading ...
Sorry, an error occurred while loading the content.

[Computational Complexity] STOC/ THEORY DAY in NY

Expand Messages
  • GASARCH
    TWO ACCOUNCEMENTS I) Reminder: STOC submission abstracts due today. = 3. Joint work with Subhash Khot. ... Prof. Joe Mitchell (Stony Brook University)
    Message 1 of 1 , Nov 10, 2008
    • 0 Attachment
      TWO ACCOUNCEMENTS

      I) Reminder: STOC submission abstracts due today.

      
      
      
      II)
      
                             New York Area Theory Day
                          Organized by:  NYU/IBM/Columbia
                          External sponsorship by: Google
                             Friday, December 5, 2008
      
      The Theory Day will be held at Courant Institute of Mathematical Sciences,
      New York University, 251 Mercer Street, Auditorium 109, New York.
      
                                      Program
      
      9:30   - 10:00    Coffee and bagels
      
      10:00  - 10:55    Prof. Assaf Naor
                       Approximate Kernel Clustering
      
      10:55  - 11:05    Short break
      
      11:05  - 12:00    Prof. Joe Mitchell
                       Approximation Algorithms for some Geometric Coverage
                       and Connectivity Problems
      
      12:00  -  2:00    Lunch break
      
       2:00  -  2:55    Dr. Jonathan Feldman
                       A Truthful Mechanism for Offline Ad Slot Scheduling
       2:55  -  3:15    Coffee break
      
       3:15  -  4:10    Prof. Yishay Mansour
                       TBA
      
      For directions, please see http://www.cims.nyu.edu/direct.html and
      http://cs.nyu.edu/csweb/Location/directions.html (building 46)
      
      To subscribe to our mailing list, follow instructions at
      http://www.cs.nyu.edu/mailman/listinfo/theory-ny
      
      Organizers:
      Yevgeniy Dodis   dodis@...
      Tal Rabin        talr@...
      Baruch Schieber  sbar@...
      Rocco Servedio  rocco@...
      
      =======================================================================
      
                              Prof. Assaf Naor
                           (New York University)
      
                       Approximate Kernel Clustering
      
      In the kernel clustering problem we are given a large n times n
      positive semi-definite matrix A=(a_{ij}) with \sum_{i,j=1}^n a_{ij}=0
      and a small k times k positive semi-definite matrix B=(b_{ij}). The
      goal is to find a partition S_1,...,S_k of {1,...n} which
      maximizes the quantity
       \sum_{i,j=1}^k (\sum_{(p,q)\in S_i\times S_j} a_{pq}) b_{ij}.
      
      We study the computational complexity of this generic clustering
      problem which originates in the theory of machine learning. We design
      a constant factor polynomial time approximation algorithm for this
      problem, answering a question posed by Song, Smola, Gretton and
      Borgwardt. In some cases we manage to compute the sharp approximation
      threshold for this problem assuming the Unique Games Conjecture
      (UGC). In particular, when B is the 3 times 3 identity matrix the UGC
      hardness threshold of this problem is exactly 16*pi/27. We present and
      study a geometric conjecture of independent interest which we show
      would imply that the UGC threshold when B is the k times k identity
      matrix is (8*pi/9)*(1-1/k) for every k >= 3.
      
      Joint work with Subhash Khot.
      
      -------------------------------------------------------------------------
      
                                Prof. Joe Mitchell
                             (Stony Brook University)
      
                        Approximation Algorithms for some
                    Geometric Coverage and Connectivity Problems
      
      We examine a variety of geometric optimization problems.  We describe
      some recent progress in improved approximations algorithms for several
      of these problems, including the TSP with neighborhoods, relay
      placement in sensor networks, and visibility/sensor coverage.  We
      highlight many open problems.
      
      -------------------------------------------------------------------------
      
                              Dr. Jonathan Feldman
                                   (Google)
      
               A Truthful Mechanism for Offline Ad Slot Scheduling
      Targeted advertising on web pages is an increasingly important
      advertising medium, attracting large numbers of advertisers and users.
      One popular method for assigning ads to various slots on a page (for
      example the slots along side web search results) is via a real-time
      auction among advertisers who have placed standing bids for clicks.
      These "position auctions" have been studied from a game-theoretic
      point of view and are now well understood as a single-shot game.
      However, since web pages are visited repeatedly over time, there are
      global phenomena at play such as supply estimates and budget
      constraints that are not modeled by this analysis.
      
      We formulate the "Offline Ad Slot Scheduling" problem, where
      advertisers are scheduled beforehand to slots on a web page for
      portions of the day.  Advertisers specify a daily budget constraint,
      as well as a per-click bid, and may not be assigned to more than one
      slot on the page during any given time period.  We give a scheduling
      algorithm and a pricing method that amount to a truthful mechanism
      under the utility model where bidders try to maximize their clicks,
      subject to their personal constraints.  In addition, we show that the
      revenue-maximizing schedule is not truthful, but has a Nash
      equilibrium whose outcome is identical to our mechanism.  Our
      mechanism employs a descending-price auction that maintains a solution
      to a machine scheduling problem whose job lengths depend on the price.
      
      Joint work with Muthu Muthukrishnan, Eddie Nikolova and Martin Pal.
      
      -------------------------------------------------------------------------
      
                               Prof. Yishay Mansour
                         (Google and Tel Aviv University)
      
                                     TBA
      
      -------------------------------------------------------------------------
      
      
      
      
      


      --
      Posted By GASARCH to Computational Complexity at 11/10/2008 12:22:00 PM
    Your message has been successfully submitted and would be delivered to recipients shortly.