@article{elmeliegy_guddati_2023, title={Correlation-based full-waveform shear wave elastography}, volume={68}, ISSN={["1361-6560"]}, url={http://dx.doi.org/10.1088/1361-6560/acc37b}, DOI={10.1088/1361-6560/acc37b}, abstractNote={Abstract}, number={11}, journal={PHYSICS IN MEDICINE AND BIOLOGY}, publisher={IOP Publishing}, author={Elmeliegy, Abdelrahman M. and Guddati, Murthy N.}, year={2023}, month={Jun} } @article{eslaminia_elmeliegy_guddati_2023, title={Improved least-squares migration through double-sweeping solver}, volume={88}, ISSN={["1942-2156"]}, url={https://doi.org/10.1190/geo2021-0628.1}, DOI={10.1190/geo2021-0628.1}, abstractNote={ Based on a recently developed approximate wave-equation solver, we have developed a methodology to reduce the computational cost of seismic migration in the frequency domain. This approach divides the domain of interest into smaller subdomains, and the wavefield is computed using a sequential process to determine the downward- and upward-propagating wavefields — hence called a double-sweeping solver. A sequential process becomes possible using a special approximation of the interface conditions between subdomains. This method is incorporated into the least-squares migration framework as an approximate solver. The associated computational effort is comparable to one-way wave-equation approaches, yet, as illustrated by the numerical examples, the accuracy and convergence behavior are comparable to that of the full-wave equation. }, number={3}, journal={GEOPHYSICS}, author={Eslaminia, Mehran and Elmeliegy, Abdelrahman M. and Guddati, Murthy N.}, year={2023}, pages={S131–S141} } @article{guddati_roy_elmeliegy_urban_2023, title={Shear wave elastography: From dispersion matching to full waveform inversion}, volume={153}, ISSN={["1520-8524"]}, DOI={10.1121/10.0018796}, abstractNote={Shear Wave Elastography (SWE) involves estimating mechanical properties through inversion, i.e., matching measured and simulated propagation characteristics of shear waves in the tissue. The accuracy of the estimated properties depends significantly on the specific characteristics/responses that are being matched. These could range from simple group velocity to dispersion curves and to full-wave response (particle velocity measurements). Using specific applications of arterial, liver, and tumor elstography, we illustrate that effective SWE is performed by resorting to an inversion approach, or combination of inversion approaches, guided by the underlying physics. To this end, we present inversion approaches ranging from matching dispersion characteristics to matching full waveform responses and provide rationale for choosing the appropriate technique(s) depending on the problem at hand.}, number={3}, journal={JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA}, author={Guddati, Murthy and Roy, Tuhin and Elmeliegy, Abdelrahman M. and Urban, Matthew W.}, year={2023}, month={Mar} } @article{eslaminia_elmeliegy_guddati_2022, title={Full waveform inversion through double-sweeping solver}, volume={453}, ISSN={["1090-2716"]}, url={https://doi.org/10.1016/j.jcp.2021.110914}, DOI={10.1016/j.jcp.2021.110914}, abstractNote={An efficient method is proposed to accurately approximate the gradient and the Hessian operator for the full-waveform inversion (FWI) in large-scale problems. The key idea is an approximate solver called double-sweeping solver, which divides the domain into smaller slabs and sequentially solves the wavefields through a downward and an upward sweeping. The sequential solution is facilitated by approximating the continuity conditions that suppress the multiples, thus relaxing long-range coupling between the subdomains. The double-sweeping solver is incorporated into an inexact Gauss-Newton approach to perform FWI, where the gradient and the Hessian vector multiplication are computed more efficiently. Through numerical experiments, we show that the convergence of FWI with respect to the number of iterations does not degrade when the double-sweeping approximation is used. Given that the double-sweeping solver is computationally cheaper than full-wave simulation, the proposed method is more efficient than the standard FWI. This paper contains the complete formulation of the proposed methodology as well as an illustration of its effectiveness to problems of varying complexity including the inversion of the Marmousi model from the Geophysics community.}, journal={JOURNAL OF COMPUTATIONAL PHYSICS}, publisher={Elsevier BV}, author={Eslaminia, Mehran and Elmeliegy, Abdelrahman M. and Guddati, Murthy N.}, year={2022}, month={Mar} } @article{elmeliegy_rashed_2019, title={Efficient Preconditioned Soil-Foundation-Structure Interaction Approach to Compute Tall-Building Time Periods}, volume={24}, ISSN={["1943-5576"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85063899035&partnerID=MN8TOARS}, DOI={10.1061/(ASCE)SC.1943-5576.0000422}, abstractNote={The present paper suggests an efficient preconditioned two-iteration substructure approach—namely, preconditioned soil–structure interaction (PSSI)—to couple the analysis of a superstructure over fixed bases (which is traditionally carried out in design companies) with the analysis of foundation plates over an elastic half-space (EHS) to obtain more accurate equivalent supporting spring stiffnesses. Hence, an accurate building time period and, consequently, lateral loads could be computed. The effectiveness of the proposed approach is illustrated in several numerical examples in terms of number of iterations and scalability followed by comparison with previous work to demonstrate the superiority of the proposed approach.}, number={3}, journal={PRACTICE PERIODICAL ON STRUCTURAL DESIGN AND CONSTRUCTION}, author={Elmeliegy, A. M. and Rashed, Youssef F.}, year={2019}, month={Aug} }