38 research outputs found
Determination of Grain-Size Distributions from Ultrasonic Attenuation
The overall research goal of this project is the nondestructive measurement of grain-size distribution parameters using ultrasonic attenuation. Ultrasonic attenuation α is dependent upon the sound wavelength (λ), the size of the grains (D), and in many cases elastic constants and sound velocities of the material. Assuming that multiple scattering can be ignored, the expression for the wavelength dependence of the attenuation is 1 α(λ)=â«0âN(D)α(λ,D)dD where N(D) is the grain-size distribution. In previous work [1] the sizes were assumed to be distributed following a power-law with exponent Îł: 2 N(D)=KDâÎł,
Low-dose CT reconstruction via L1 dictionary learning regularization using iteratively reweighted least-squares
Symbolic-Numeric Methods for Nonlinear Integro-Differential Modeling
International audienceThis paper presents a proof of concept for symbolic and numeric methods dedicated to the parameter estimation problem for models formulated by means of nonlinear integro-differential equations (IDE). In particular, we address: the computation of the model input-output equation and the numerical integration of IDE systems