Cooperation of the partial differential equation methods and the wavelet transform for the segmentation of multivalued images

2008 ◽  
Vol 23 (1) ◽  
pp. 14-30 ◽  
Author(s):  
Aldo Maalouf ◽  
Philippe Carré ◽  
Bertrand Augereau ◽  
Christine Fernandez-Maloigne
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Wavelet Transform ◽  
Partial Differential ◽  
Multivalued Images

De-Noising Method for Partial Discharge Signal Based on Wavelet Transform and Partial Differential Equation

2014 ◽  
Vol 529 ◽  
pp. 444-447 ◽  
Author(s):  
Jian Zhang ◽  
Fu Jiang Mo ◽  
Feng Yao ◽  
Xiao Jian Wang
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Wavelet Transform ◽  
Noise Suppression ◽  
Partial Discharge ◽  
Interference Signal ◽  
Partial Differential ◽  
Calculation Results ◽  
Low Distortion

In order to solve the noise suppression problem in partial discharge (PD) signals detection, this paper proposes a de-noising method based on wavelet transform and partial differential equation (PDE). Compared the effect of proposed method with traditional wavelet threshold de-noising method, simulation and calculation results both show that paper’s method can remove the interference signal, retain the better edge detail of signal and low distortion when taking the appropriate iteration times.

Qxygen transfer in gravity flow sewers

2000 ◽  
Vol 42 (3-4) ◽  
pp. 417-422 ◽  
Author(s):  
T.Y. Pai ◽  
C.F. Ouyang ◽  
Y.C. Liao ◽  
H.G. Leu
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Dissolved Oxygen ◽  
Flow Velocity ◽  
Molecular Diffusion ◽  
Eddy Diffusion ◽  
Partial Differential ◽  
Diffusion Term ◽  
Sewer Pipes ◽  
Gravity Sewer

Oxygen diffused to water in gravity sewer pipes was studied in a 21 m long, 0.15 m diameter model sewer. At first, the sodium sulfide was added into the clean water to deoxygenate, then the pump was started to recirculate the water and the deoxygenated water was reaerated. The dissolved oxygen microelectrode was installed to measure the dissolved oxygen concentrations varied with flow velocity, time and depth. The dissolved oxygen concentration profiles were constructed and observed. The partial differential equation diffusion model that considered Fick's law including the molecular diffusion term and eddy diffusion term were derived. The analytic solution of the partial differential equation was used to determine the diffusivities by the method of nonlinear regression. The diffusivity values for the oxygen transfer was found to be a function of molecular diffusion, eddy diffusion and flow velocity.

Sign in / Sign up

Export Citation Format

Share Document