Page 1

Displaying 1 – 5 of 5

Showing per page

An efficient estimator for Gibbs random fields

Martin Janžura (2014)

Kybernetika

An efficient estimator for the expectation f P ̣ is constructed, where P is a Gibbs random field, and f is a local statistic, i. e. a functional depending on a finite number of coordinates. The estimator coincides with the empirical estimator under the conditions stated in Greenwood and Wefelmeyer [6], and covers the known special cases, namely the von Mises statistic for the i.i.d. underlying fields and the case of one-dimensional Markov chains.

Application of the random field theory in PET imaging - injection dose optimization

Jiří Dvořák, Jiří Boldyš, Magdaléna Skopalová, Otakar Bělohlávek (2013)

Kybernetika

This work presents new application of the random field theory in medical imaging. Results from both integral geometry and random field theory can be used to detect locations with significantly increased radiotracer uptake in images from positron emission tomography (PET). The assumptions needed to use these results are verified on a set of real and simulated phantom images. The proposed method of detecting activation (locations with increased radiotracer concentration) is used to quantify the quality...

Approximation of the fractional Brownian sheet VIA Ornstein-Uhlenbeck sheet

Laure Coutin, Monique Pontier (2007)

ESAIM: Probability and Statistics

A stochastic “Fubini” lemma and an approximation theorem for integrals on the plane are used to produce a simulation algorithm for an anisotropic fractional Brownian sheet. The convergence rate is given. These results are valuable for any value of the Hurst parameters ( α 1 , α 2 ) ] 0 , 1 [ 2 , α i 1 2 . Finally, the approximation process is iterative on the quarter plane + 2 . A sample of such simulations can be used to test estimators of the parameters αi,i = 1,2.

Currently displaying 1 – 5 of 5

Page 1