54,698 research outputs found

    A unifying representation for a class of dependent random measures

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    We present a general construction for dependent random measures based on thinning Poisson processes on an augmented space. The framework is not restricted to dependent versions of a specific nonparametric model, but can be applied to all models that can be represented using completely random measures. Several existing dependent random measures can be seen as specific cases of this framework. Interesting properties of the resulting measures are derived and the efficacy of the framework is demonstrated by constructing a covariate-dependent latent feature model and topic model that obtain superior predictive performance

    Noncommutative Dynamics of Random Operators

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    We continue our program of unifying general relativity and quantum mechanics in terms of a noncommutative algebra A{\cal A} on a transformation groupoid Γ=E×G\Gamma = E \times G where EE is the total space of a principal fibre bundle over spacetime, and GG a suitable group acting on Γ\Gamma . We show that every a∈Aa \in {\cal A} defines a random operator, and we study the dynamics of such operators. In the noncommutative regime, there is no usual time but, on the strength of the Tomita-Takesaki theorem, there exists a one-parameter group of automorphisms of the algebra A{\cal A} which can be used to define a state dependent dynamics; i.e., the pair (A,ϕ)({\cal A}, \phi), where ϕ\phi is a state on A{\cal A}, is a ``dynamic object''. Only if certain additional conditions are satisfied, the Connes-Nikodym-Radon theorem can be applied and the dependence on ϕ\phi disappears. In these cases, the usual unitary quantum mechanical evolution is recovered. We also notice that the same pair (A,ϕ)({\cal A}, \phi) defines the so-called free probability calculus, as developed by Voiculescu and others, with the state ϕ\phi playing the role of the noncommutative probability measure. This shows that in the noncommutative regime dynamics and probability are unified. This also explains probabilistic properties of the usual quantum mechanics.Comment: 13 pages, LaTe

    Measuring economic inequality and risk: a unifying approach based on personal gambles, societal preferences and references

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    The underlying idea behind the construction of indices of economic inequality is based on measuring deviations of various portions of low incomes from certain references or benchmarks, that could be point measures like population mean or median, or curves like the hypotenuse of the right triangle where every Lorenz curve falls into. In this paper we argue that by appropriately choosing population-based references, called societal references, and distributions of personal positions, called gambles, which are random, we can meaningfully unify classical and contemporary indices of economic inequality, as well as various measures of risk. To illustrate the herein proposed approach, we put forward and explore a risk measure that takes into account the relativity of large risks with respect to small ones.Comment: 29 pages, 4 figure

    Location Dependent Dirichlet Processes

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    Dirichlet processes (DP) are widely applied in Bayesian nonparametric modeling. However, in their basic form they do not directly integrate dependency information among data arising from space and time. In this paper, we propose location dependent Dirichlet processes (LDDP) which incorporate nonparametric Gaussian processes in the DP modeling framework to model such dependencies. We develop the LDDP in the context of mixture modeling, and develop a mean field variational inference algorithm for this mixture model. The effectiveness of the proposed modeling framework is shown on an image segmentation task
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