Upcoming Talks  

This is a list of all upcoming talks for the next two weeks. Talks are from 3:45-4:45 p.m. in the Colloquium or Seminar Room, unless otherwise specified.

  • Oct 24
    Hallucination Helps: Energy Efficient Virtual Circuit Routing Prof. Clifford Stein Columbia University Time: 12:00 PM Colloquium

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    In this talk, we give online and offline approximation algorithms for energy efficient circuit routing protocols for a network of components that are speed scalable, and that may be shutdown when idle. We will consider both the case where the speed-scalable components are edges and the case when they are nodes. For the case of edges, we describe a polynomial-time offline algorithm that has a poly-log approximation ratio. The key step of the algorithm design is a random sampling technique that we call hallucination. The algorithm extends rather naturally to an online algorithm. The analysis of the online algorithm introduces a natural ``priority'' multicommodity flow problem, and bounds the priority multicommodity flow-cut gap. We will then explain the additional difficulty faced if the power management components are vertices, and explain how to how to surmount this difficulty in the offline case. This work spans several papers and is joint with Antonios Antoniadis, Nikhil Bansal, Sungjin Im, Ravishankar Krishnaswamy, Benjamin Moseley, Viswanath Nagarajan, Kirk Pruhs.
  • Nov 03
    Extendable endomorphisms of factors (part 2) Prof. Alexis Alevras USNA Time: 03:45 PM Operator Algebras and Dynamics Seminars

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    An endomorphism of a factor M acting standardly on a Hilbert space H gives rise, via the conjugation operator, to an endomorphism of the commutant M'. The endomorphism is called extendable if there is a simultaneous extension of the actions on M and M' to an endomorphism of B(H). We will review recent results of Bikram, Izumi, Srinivasan and Sunder on extendability, with applications to the classification of endomorphism semigroups of factors of type II and III.
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