نتایج جستجو برای: di usion model

تعداد نتایج: 2335429  

Journal: :نظریه تقریب و کاربرد های آن 0
m khanian department of mathematics, khorasgan (isfahan) branch, islamic azad university, isfahan, iran. a. davari department of mathematics, faculty of sciences, university of isfahan, isfahan, iran.

image restoration has been an active research area. di erent formulations are e ective in high qualityrecovery. partial di erential equations (pdes) have become an important tool in image processingand analysis. one of the earliest models based on pdes is perona-malik model that is a kindof anisotropic di usion (andi) lter. anisotropic di usion lter has become a valuable tool indi erent elds...

Journal: :نظریه تقریب و کاربرد های آن 0
h. vosoughi department of mathematics, faculty of science, islamshahr branch, islamic azad university, islamshahr, tehran, iran e. shivanian department of mathematics, imam khomeini international university, qazvin, 34149-16818, iran m. anbarloei department of mathematics, faculty of science, islamshahr branch, islamic azad university, islamshahr, tehran, iran

the purpose of this letter is to revisit the nonlinear reaction-di usion modelin porous catalysts when reaction term is fractional function of the concen-tration distribution of the reactant. this model, which originates also in uidand solute transport in soft tissues and microvessels, has been recently givenanalytical solution in terms of taylors series for di erent family of reactionterms. we...

2001
Brian L. Evans

Traditional error di usion halftoning produces high quality binary images from digital grayscale images. Error di usion shapes the quantization noise power into the high frequency regions where the human eye is the least sensitive. Error di usion may be extended to color images by using error lters with matrix-valued coe cients to take into account the correlation among color planes. We propose...

2000
B. I. Henry S. L. Wearne

We derive a fractional reaction–di usion equation from a continuous-time random walk model with temporal memory and sources. The equation provides a general model for reaction–di usion phenomena with anomalous di usion such as occurs in spatially inhomogeneous environments. As a rst investigation of this equation we consider the special case of single species fractional reaction–di usion in one...

2001
Niranjan Damera-Venkata Brian L. Evans

Traditional error di usion halftoning is a high quality method for producing binary images from digital grayscale images. Error di usion shapes the quantization noise power into the high frequency regions where the human eye is the least sensitive. Error di usion may be extended to color images by using error lters with matrix-valued coe cients to take into account the correlation among color p...

2002
Floyd B. Hanson J. J. Westman

The stochastic analysis is presented for the parameter estimation problem for tting a theoretical jump-di usion model to the log-returns from closing data of the Standard and Poor's 500 (S&P500) stock index during the prior decade 1992-2001. The jump-di usion model combines a the usual geometric Brownian motion for the di usion and a space-time Poisson process for the jumps such that the jump a...

1998
Ping Liang

A novel local scale controlled piecewise linear di usion for selective smoothing and edge detection is presented. The di usion stops at the place and time determined by the minimum reliable local scale and a spatial variant, anisotropic local noise estimate. It shows nisotropic, nonlinear di usion equation using di usion coe cients/tensors that continuously depend on the gradient is not necessa...

2003
Vishal Monga

Conventional grayscale error di usion halftoning produces worms and other objectionable artifacts. Tone Dependent error di usion for grayscale halftoning (Li and Allebach) helps reduce these artifacts by controlling di usion of quantization errors based on the input graylevel value. Allebach et al. design error lters weights and thresholds for each (input) graylevel optimized based on a human v...

2014
Harsha Honnappa Rahul Jain Amy Ward Ming Hsieh

Abstract We study a queueing model with ordered arrivals, which can be called the (i)/GI/1 queue. Here, customers from a fixed, finite, population independently sample a time to arrive from some given distribution F , and enter the queue in order of the sampled arrival times. Thus, the arrival times are order statistics, and the inter-arrival times are di↵erences of consecutive ordered statisti...

2002
N. V. Krylova

Convergence of stochastic processes with jumps to di!usion processes is investigated in the case when the limit process has discontinuous coe$cients. An example is given in which the diffusion approximation of a queueing model yields a di!usion process with discontinuous di!usion and drift coe$cients. c © 2002 Elsevier Science B.V. All rights reserved. MSC: 60B10; 60K25

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