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991.
The effects on the noise content of producing a projection from a stack of confocal images are investigated. Processing by retaining either the mean or peak pixel value is found to reduce noise, with the former giving more noise reduction. Gaussian noise, shot noise and speckle are considered. The effects of processing on the perception of the images are discussed. 相似文献
992.
Zheng Yan LIN Wen Sheng WANG Kyo Shin HWANG 《数学学报(英文版)》2006,22(6):1767-1780
In this paper, we obtain functional limit theorems for d-dimensional FBM in HSlder norm via estimating large deviation probabilities for d-dimensional FBM in HSlder norm. 相似文献
993.
S. G. Kobel’kov 《Mathematical Notes》2006,80(3-4):372-379
For a family of real-valued Gaussian processes ξ u (t), t ∈ [0, T], we obtain an exact asymptotics of the probability of crossing a level u as u → ∞ under certain conditions on the variance and correlation. This result is applied to the investigation of excursions of a stationary zero-mean process above a barrier increasing to infinity. 相似文献
994.
A note on fast Fourier transforms for nonequispaced grids 总被引:1,自引:0,他引:1
Gabriele Steidl 《Advances in Computational Mathematics》1998,9(3-4):337-352
In this paper, we are concerned with fast Fourier transforms for nonequispaced grids. We propose a general efficient method
for the fast evaluation of trigonometric polynomials at nonequispaced nodes based on the approximation of the polynomials
by special linear combinations of translates of suitable functions ϕ. We derive estimates for the approximation error. In particular, we improve the estimates given by Dutt and Rokhlin [7].
As a practical consequence, we obtain a criterion for the choice of the parameters involved in the fast transforms.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
995.
996.
L. E. Wedgewood 《Rheologica Acta》1993,32(4):405-417
The Gaussian closure method and Brownian dynamics simulations have been used to calculate the shear material properties of a dilute solution of Hookean dumbbells with internal viscosity. Results for the zero-shear-rate material properties and small amplitude oscillatory shear material properties have been found analytically, and numerical results for the steady state shear material properties are also presented. Two interpretations of the stress tensor are investigated and results are compared. Brownian dynamics simulations are used to obtain material properties of the Hookean dumbbell with internal viscosity without approximations. These simulation results are compared with the perturbation solution of Booij and van Wiechen as well as with a new Gaussian closure solution. Also presented are the contracted distribution functions as derived from the Gaussian closure method and from Brownian dynamics simulations. 相似文献
997.
This paper studies the heavy-traffic behavior of a closed system consisting of two service stations. The first station is
an infinite server and the second is a single server whose service rate depends on the size of the queue at the station. We
consider the regime when both the number of customers, n, and the service rate at the single-server station go to infinity while the service rate at the infinite-server station is
held fixed. We show that, as n→∞, the process of the number of customers at the infinite-server station normalized by n converges in probability to a deterministic function satisfying a Volterra integral equation. The deviations of the normalized
queue from its deterministic limit multiplied by √n converge in distribution to the solution of a stochastic Volterra equation.
The proof uses a new approach to studying infinite-server queues in heavy traffic whose main novelty is to express the number
of customers at the infinite server as a time-space integral with respect to a time-changed sequential empirical process.
This gives a new insight into the structure of the limit processes and makes the end results easy to interpret. Also the approach
allows us to give a version of the classical heavy-traffic limit theorem for the G/GI/∞ queue which, in particular, reconciles the limits obtained earlier by Iglehart and Borovkov.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
998.
999.
G. Kjellström 《Journal of Optimization Theory and Applications》1991,69(1):185-187
This contribution to the debate on Monte Carlo optimization methods shows that there exist techniques that may be useful in many technical applications. 相似文献
1000.
This paper is the continuation of [1] in which complex symmetries of distributions and their covariance operators are investigated. Here we also study the most general quaternion symmetries of random vectors. Complete classification theorems on these symmetries are proved in terms of covariance operator spectra. 相似文献