DSpace at MIT
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Accelerated clustering through locality-sensitive hashing - Kishore, Shaunak
We obtain improved running times for two algorithms for clustering data: the expectation-maximization (EM) algorithm and Lloyd's algorithm. The EM algorithm is a heuristic for finding a mixture of k normal distributions in Rd that maximizes the probability of drawing n given data points. Lloyd's algorithm is a special case of this algorithm in which the covariance matrix of each normally-distributed component is required to be the identity. We consider versions of these algorithms where the number of mixture components is inferred by assuming a Dirichlet process as a generative model. The separation probability of this process, [alpha], is typically...
Computational neutronics analysis of TRIGA reactors during power pulsing - Bean, Malcolm (Malcolm K.)
Training, Research, Isotopes, General Atomics (TRIGA) reactors have the unique capability of generating high neutron flux environments with the removal of a transient control rod, creating conditions observed in fast fission reactors. Recently, several TRIGA reactors have had issues with the deformation of fuel rods nearest the transient control rod, where the neutron flux is highest. This is a difficult problem to analyze because the damage is not simply due to rods overheating, but rather the pressurization of hydrogen, from the Uranium Hydride fuel, that has diffused into the spacing between fuel and cladding. Previous neutronic analyses utilized point kinetics;...
An economic history of five midwestern railroads. - Kaitz, Gary Marshall
Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning; and, (B.S.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1977.
Identifying boosted objects with N-subjettiness and linear k-means clustering - Van Tilburg, Ken
In this thesis, I explore aspects of a new jet shape - N-subjettiness - designed to identify boosted hadronically-decaying objects (with a particular focus on tagging top quarks) at particle accelerators such as the Large Hadron Collider. Combined with an invariant mass cut on jets, N-subjettiness is a powerful discriminating variable for tagging boosted objects such as top quarks and rejecting the fake background of QCD jets with large invariant mass. In a crossover analysis, the N-subjettiness method is found to outperform the common top tagging methods of the BOOST2010 conference, with top tagging efficiencies of 50% and 20% against...
Definite integrals - Mannos, Murray
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1937.
The dynamics of enzymatic switch cascades - Mukherji, Shankar, 1982-
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics; and, (S.B.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2004.