[Newsletter.]
 


July 2004

Candidate: Michael Rosenblum Abstract: We consider the problem of providing flexible, rate-based, quality of service guarantees for packets sent over switches and switch networks. Our focus is solving a type of on-line, traffic scheduling problem, whose input at each time step is a set of desired traffic rates through the switch network. These traffic rates in general cannot be exactly achieved since they treat the incoming data as fluid, that is, they assume arbitrarily small fractions of packets can be transmitted at each time step. The goal of the traffic scheduling problem is to closely approximate the given sequence of traffic rates by a sequence of switch uses throughout the network in which only whole packets are sent. We prove worst-case bounds on the additional delay and buffer use that result from using such an approximation. These bounds depend on the network topology, the resources available to the scheduler, and the types of fluid policy allowed.
Title: Approximating fluid schedules in packet-switched networks
Date: Friday July 23, 2004
Time: 2:30 pm
Location: Room 1-135
Committee: Vahid Tarokh (Harvard), co-thesis advisor
Michel Goemans, co-thesis advisor
Daniel Spielman

Candidate: Morten Honsen Abstract: We define a moduli functor parametrizing finite maps from a projective (locally) Cohen-Macaulay curve to a fixed projective space. The definition of the functor includes a number of technical conditions, but the most important is that the map is almost everywhere an isomorphism onto its image. The motivation for this definition comes from trying to interpolate between the Hilbert scheme and the Kontsevich mapping space. The main result of this thesis is that our functor is represented by a proper algebraic space. As an application we obtain interesting compactifications of the spaces of smooth curves in projective space. We illustrate this in the case of rational quartics, where the resulting space appears easier than the Hilbert scheme.
Title: A compact moduli space parameterizing Cohen-Macaulay curves in projective space
Date: Thursday July 29, 2004
Time: 12:00 pm
Location: Room 1-150
Committee: Johan DeJong, thesis advisor
Jason Starr
Kiran Kedlaya


August 2004

Candidate: Benoit Charbonneau Abstract: The main result is a computation of the Nahm transform of a SU(2)-instanton over blackboard bold R x T3, called spatially-periodic instanton. It is a singular monopole over T3, a solution to the Bogomolny equation, whose rank is computed and behavior at the singular points is understood under certain conditions.

A full description of the Riemannian ADHMN construction of instantons on blackboard bold R4 is given, preceding a description of the heuristic behind the theory of instantons on quotients of blackboard bold R4. The Fredholm theory of twisted Dirac operators on cylindrical manifolds is derived, the spectra of spin Dirac operators on spheres and on product manifolds are computed. A brief discussion on the decay of spatially-periodic and doubly-periodic instantons is included.

Title: Analytic aspects of periodic instantons
Date: Thursday August 5, 2004
Time: 10:00 am
Location: Room 2-102
Committee: Tomasz Mrowka, thesis advisor
Victor Guillemin
Peter Kronheimer (Harvard)

Other Thesis Defenses

Current Term Thesis Defenses
 
Summer 2005 Thesis Defenses
 
Spring 2005 Thesis Defenses
 
Fall 2004 Thesis Defenses
 
Summer 2004 Thesis Defenses
 
Spring 2004 Thesis Defenses
 
Fall 2003 Thesis Defenses
 
Summer 2003 Thesis Defenses
 
Spring 2003 Thesis Defenses
 
Fall 2002 Thesis Defenses
 
Spring 2002 Thesis Defenses