scholarly journals Kronecker product approximation preconditioners for convection-diffusion model problems

2009 ◽  
Vol 17 (4) ◽  
pp. 691-712 ◽  
Author(s):  
Hua Xiang ◽  
Laura Grigori
Keyword(s):  
Diffusion Model ◽  
Kronecker Product ◽  
Convection Diffusion

An Anisotropic Convection-Diffusion Model Using Tailored Finite Point Method for Image Denoising and Compression

2016 ◽  
Vol 19 (5) ◽  
pp. 1357-1374
Author(s):  
Yu-Tuan Lin ◽  
Yin-Tzer Shih ◽  
Chih-Ching Tsai
Keyword(s):  
Image Denoising ◽  
Diffusion Model ◽  
Point Method ◽  
Grid Structure ◽  
Finite Point ◽  
Convection Diffusion ◽  
Finite Point Method ◽  
Tailored Finite Point Method ◽  
Tailored Finite Point ◽  
Salt And Pepper

AbstractIn this paper we consider an anisotropic convection-diffusion (ACD) filter for image denoising and compression simultaneously. The ACD filter is discretized by a tailored finite point method (TFPM), which can tailor some particular properties of the image in an irregular grid structure. A quadtree structure is implemented for the storage in multi-levels for the compression. We compare the performance of the proposed scheme with several well-known filters. The numerical results show that the proposed method is effective for removing a mixture of white Gaussian and salt-and-pepper noises.

Development of Parallel Program of Two-Dimensional Flow-Sediment Mathematical Model for Long River Reach

2013 ◽  
Vol 779-780 ◽  
pp. 1562-1566
Author(s):  
Jian Jun Wang
Keyword(s):  
Diffusion Model ◽  
Yangtze River ◽  
Parallel Program ◽  
The Yangtze River ◽  
Parallel Efficiency ◽  
Convection Diffusion ◽  
Technical Requirements ◽  
Parallel Speedup ◽  
River Reach ◽  
Special Points

In order to meet technical requirements for systematic regulation to long reach of the Yangtze River, parallel program to computing core part of the software is developed based on TK-2DC software, which mainly contains parallelization research on flow convection diffusion model and sediment convection diffusion model. This parallel program conducts parallel programming on the basis of MPI. The whole parallel computing part adopts peer mode and corresponding special processing is performed to solving method of equation and special points so as to obtain better parallel speedup and parallel efficiency. Parallel program has been tested by relying on channel regulation engineering related to Jingjiang reach in the middle reach of the Yangtze River. Test results shows that parallel efficiency with 8 CPU is up to 80% and parallel speedup can reach 4.98. Flow-sediment analog computing efficiency of long river reach is greatly improved.

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