Results 1 - 10 of 8,373

Axiomatic quantum field theory in curved spacetime

by Stefan Hollands, Robert M. Wald , 2008
"... The usual formulations of quantum field theory in Minkowski spacetime make crucial use of features—such as Poincare invariance and the existence of a preferred vacuum state—that are very special to Minkowski spacetime. In order to generalize the formulation of quantum field theory to arbitrary globa ..."
Abstract - Cited by 689 (18 self) - Add to MetaCart
and covariantly constructed from the spacetime metric), a microlocal spectrum condition, an "associativity" condition, and the requirement that the coefficient of the identity in the OPE of the product of a field with its adjoint have positive scaling degree. We prove curved spacetime versions

Kernel-Based Object Tracking

by Dorin Comaniciu, Visvanathan Ramesh, Peter Meer , 2003
"... A new approach toward target representation and localization, the central component in visual tracking of non-rigid objects, is proposed. The feature histogram based target representations are regularized by spatial masking with an isotropic kernel. The masking induces spatially-smooth similarity fu ..."
Abstract - Cited by 900 (4 self) - Add to MetaCart
functions suitable for gradient-based optimization, hence, the target localization problem can be formulated using the basin of attraction of the local maxima. We employ a metric derived from the Bhattacharyya coefficient as similarity measure, and use the mean shift procedure to perform the optimization

Homological Algebra of Mirror Symmetry

by Maxim Kontsevich - in Proceedings of the International Congress of Mathematicians , 1994
"... Mirror Symmetry was discovered several years ago in string theory as a duality between families of 3-dimensional Calabi-Yau manifolds (more precisely, complex algebraic manifolds possessing holomorphic volume elements without zeroes). The name comes from the symmetry among Hodge numbers. For dual Ca ..."
Abstract - Cited by 523 (3 self) - Add to MetaCart
Calabi-Yau manifolds V, W of dimension n (not necessarily equal to 3) one has dim H p (V, Ω q) = dim H n−p (W, Ω q). Physicists conjectured that conformal field theories associated with mirror varieties are equivalent. Mathematically, MS is considered now as a relation between numbers of rational curves

Estimating the Support of a High-Dimensional Distribution

by Bernhard Schölkopf, John C. Platt, John Shawe-taylor, Alex J. Smola, Robert C. Williamson , 1999
"... Suppose you are given some dataset drawn from an underlying probability distribution P and you want to estimate a "simple" subset S of input space such that the probability that a test point drawn from P lies outside of S is bounded by some a priori specified between 0 and 1. We propo ..."
Abstract - Cited by 783 (29 self) - Add to MetaCart
of the weight vector in an associated feature space. The expansion coefficients are found by solving a quadratic programming problem, which we do by carrying out sequential optimization over pairs of input patterns. We also provide a preliminary theoretical analysis of the statistical performance of our

Capacity of a Mobile Multiple-Antenna Communication Link in Rayleigh Flat Fading

by Thomas L. Marzetta, Bertrand M. Hochwald
"... We analyze a mobile wireless link comprising M transmitter and N receiver antennas operating in a Rayleigh flat-fading environment. The propagation coefficients between every pair of transmitter and receiver antennas are statistically independent and unknown; they remain constant for a coherence int ..."
Abstract - Cited by 495 (22 self) - Add to MetaCart
We analyze a mobile wireless link comprising M transmitter and N receiver antennas operating in a Rayleigh flat-fading environment. The propagation coefficients between every pair of transmitter and receiver antennas are statistically independent and unknown; they remain constant for a coherence

On Association Coefficients, Correction for Chance, and Correction for Maximum Value

by Matthijs J. Warrens
"... This paper studied correction for chance and correction for maximum value as functions on a space of association coefficients. Various properties of both functions are presented. It is shown that the two functions commute under composition; and that the composed function maps a coefficient and all i ..."
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This paper studied correction for chance and correction for maximum value as functions on a space of association coefficients. Various properties of both functions are presented. It is shown that the two functions commute under composition; and that the composed function maps a coefficient and all

Mixed Logit with Repeated Choices: Households' Choices Of Appliance Efficiency Level

by David Revelt, Kenneth Train , 1997
"... : Mixed logit models, also called random-parameters or error-components logit, are a generalization of standard logit that do not exhibit the restrictive "independence from irrelevant alternatives" property and explicitly account for correlations in unobserved utility over repeated choices ..."
Abstract - Cited by 338 (10 self) - Add to MetaCart
of Appliance Efficiency Level 1. Introduction Mixed logit (also called random-parameters logit) generalizes standard logit by allowing the parameter associated with each observed variable (e.g., its coefficient) to vary randomly across customers. The moments of the distribution of customer

Bayesian Compressive Sensing

by Shihao Ji, Ya Xue, Lawrence Carin , 2007
"... The data of interest are assumed to be represented as N-dimensional real vectors, and these vectors are compressible in some linear basis B, implying that the signal can be reconstructed accurately using only a small number M ≪ N of basis-function coefficients associated with B. Compressive sensing ..."
Abstract - Cited by 330 (24 self) - Add to MetaCart
The data of interest are assumed to be represented as N-dimensional real vectors, and these vectors are compressible in some linear basis B, implying that the signal can be reconstructed accurately using only a small number M ≪ N of basis-function coefficients associated with B. Compressive sensing

Nonlinear spatial normalization using basis functions

by John Ashburner, Karl J. Friston - Human Brain Mapping , 1999
"... Abstract: We describe a comprehensive framework for performing rapid and automatic nonlabel-based nonlinear spatial normalizations. The approach adopted minimizes the residual squared difference between an image and a template of the same modality. In order to reduce the number of parameters to be f ..."
Abstract - Cited by 329 (19 self) - Add to MetaCart
to be fitted, the nonlinear warps are described by a linear combination of low spatial frequency basis functions. The objective is to determine the optimum coefficients for each of the bases by minimizing the sum of squared differences between the image and template, while simultaneously maximizing

Symplectic reflection algebras, Calogero-Moser space, and deformed Harish-Chandra homomorphism

by Pavel Etingof, Victor Ginzburg - Invent. Math
"... To any finite group Γ ⊂ Sp(V) of automorphisms of a symplectic vector space V we associate a new multi-parameter deformation, Hκ, of the algebra C[V]#Γ, smash product of Γ with the polynomial algebra on V. The parameter κ runs over points of CP r, where r = number of conjugacy classes of symplectic ..."
Abstract - Cited by 280 (39 self) - Add to MetaCart
To any finite group Γ ⊂ Sp(V) of automorphisms of a symplectic vector space V we associate a new multi-parameter deformation, Hκ, of the algebra C[V]#Γ, smash product of Γ with the polynomial algebra on V. The parameter κ runs over points of CP r, where r = number of conjugacy classes of symplectic
Results 1 - 10 of 8,373