34,660 research outputs found
Diagonal quantum Bianchi type IX models in N=1 supergravity
We take the general quantum constraints of N=1 supergravity in the special
case of a Bianchi metric, with gravitino fields constant in the invariant
basis. We construct the most general possible wave function which solves the
Lorentz constraints and study the supersymmetry constraints in the Bianchi
Class A Models. For the Bianchi-IX cases, both the Hartle-Hawking state and
wormhole state are found to exist in the middle fermion levels.Comment: plain LaTex, 17 pages, accepted for publication in Classical Quantum
Gravit
Mixtures of Common Skew-t Factor Analyzers
A mixture of common skew-t factor analyzers model is introduced for
model-based clustering of high-dimensional data. By assuming common component
factor loadings, this model allows clustering to be performed in the presence
of a large number of mixture components or when the number of dimensions is too
large to be well-modelled by the mixtures of factor analyzers model or a
variant thereof. Furthermore, assuming that the component densities follow a
skew-t distribution allows robust clustering of skewed data. The alternating
expectation-conditional maximization algorithm is employed for parameter
estimation. We demonstrate excellent clustering performance when our model is
applied to real and simulated data.This paper marks the first time that skewed
common factors have been used
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