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We present a general method for estimating the location of small, well-separated scatterers in a randomly inhomogeneous environment using an active sensor array. The main features of this method are (i) an arrival time analysis of the echo received from the scatterers, (ii) a singular value decomposition of the array response matrix in the frequency domain,… (More)

Analytical expressions for three P-wave attenuation mechanisms in sedimentary rocks are given a unified theoretical framework. Two of the models concern wave-induced flow due to heterogeneity in the elastic moduli at " mesoscopic " scales (scales greater than grain sizes but smaller than wavelengths). In the first model, the heterogeneity is due to… (More)

We review the theory of iterative optimization, revealing the common origin of diierent optimization methods and reformulating the pseudoinverse, model resolution , and data resolution operators in terms of eeective iterative estimates. Examples from crosswell tomography illustrate the theory and suggest eecient methods of its implementation.

- Steven R Pride, James G Berryman
- Physical review. E, Statistical, nonlinear, and…
- 2003

The equations governing the linear acoustics of composites with two isotropic porous constituents are derived from first principles using volume-averaging arguments. The theory is designed for modeling acoustic propagation through heterogeneous porous structures. The only restriction placed on the geometry of the two porous phases is that the overall… (More)

- Steven R Pride, James G Berryman
- Physical review. E, Statistical, nonlinear, and…
- 2003

For the purpose of understanding the acoustic attenuation of double-porosity composites, the key macroscopic equations are those controlling the fluid transport. Two types of fluid transport are present in double-porosity dual-permeability materials: (1) a scalar transport that occurs entirely within each averaging volume and that accounts for the rate at… (More)

Reconstruction of acoustic, seismic, or electromagnetic wave speed distribution from rst arrival traveltime data is the goal of traveltime tomography. The reconstruction problem is nonlinear, because the ray paths that should be used for tomographic backprojection techniques can depend strongly on the unknown wave speeds. In our analysis, Fermat's principle… (More)

{ Methods are developed for design of linear tomographic reconstruction algorithms with speciied properties. Assuming a starting model with constant slowness, an algorithm with the following properties is found: (1) The optimum constant for the starting model is determined automatically. (2) The weighted least-squares error between the predicted and… (More)

Fermat's principle shows that a deenite convex set of feasible slowness models { depending only on the traveltime data { exists for the fully nonlinear traveltime inversion problem. In a new iterative reconstruction algorithm, the minimum number of nonfeasible ray paths is used as a gure of merit to determine the optimum size of the model correction at each… (More)

The task of electrical impedance tomography is to invert electrical boundary measurements for the conductivity distribution of a body. This inverse problem can be formulated so the primary data are the measured powers dissipated across injection electrodes. Then, since these powers are minima of the pertinent variational principles (Dirichlet's or Thomson's… (More)

For practical applications of variational bounds to the eeective properties of composite materials, the information available is often not that required by the formulas for the optimal bounds. It is therefore important to determine what can be said rigorously about various unknown material properties when some other properties are known. The key quantities… (More)