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Skip to Search Results- 17Sacchi, Mauricio (Physics)
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- 1Le, Lawrence (Radiology and Diagnostic Imaging)
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Acoustic and elastic least-squares two-way wave equation migration with exact adjoint operator
DownloadSpring 2017
A major problem in exploration seismology entails estimating subsurface structures and properties via linearized inversion. The problem is often called ''least-squares migration" where seismic imaging is posed as an iterative least-squares problem. The iterative solution employs the method of...
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Fall 2019
Osteoporosis is currently the most common metabolic musculoskeletal disease which causes brittle bones with a consequent increase in bone fragility and susceptibility to fracture. This “silent epidemic” is mainly characterized by the loss of bone mass, micro-structural deterioration, and cortical...
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Efficient algorithms for least squares wave equation migration and source signature estimation
DownloadFall 2017
Estimating accurate images of the subsurface is one of the end products of seismic data processing. Numerical solutions to the wave equation allow designing linearized forward operators. The adjoint of the linearized forward operator is used to image the interior of the earth. The adjoint...
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Elastic Least-squares Reverse Time Migration and Elastic Gauss-Newton Full-waveform Inversion
DownloadFall 2018
With the fast development of high-performance computing resources, imaging and inversion techniques in the exploration geophysics community are moving from simplified methods to more complex methods that honour as far as possible the physics of wave propagation. Multiparameter imaging and...
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Gradient projection methods with applications to simultaneous source seismic data processing
DownloadFall 2017
Simultaneous source acquisition, or blended acquisition, has become an important strategy to reduce the cost of seismic surveys by allowing overlapping between different sources. The major technical challenge associated with this acquisition design is the strong interferences caused by the...
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Fall 2020
This thesis proposes a framework for ground roll removal based on regularized inversion. Both ground roll and reflections are represented in the frequency-space (f - x) domain as a linear function of unknown complex amplitudes. An inversion algorithm is developed to estimate the coefficients that...
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Fall 2022
Vector field data are becoming increasingly more common in several fields of signal processing, such as electrical engineering and geophysics. Processing vector-valued signals, however, has imposed a series of challenges on its practitioners. Many approaches can be taken to carry out vector field...
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Imaging bone fractures using ultrasonic scattered wavefields: numerical and in-vitro studies
DownloadFall 2011
Ultrasound has been widely used in medical diagnostic imaging to image soft tissues. Compared with other methods, ultrasound is superior with no ionizing-radiation, easy portability, low cost, and the capability to provide elasticity information. Conventional ultrasound images provide distorted...
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Fall 2020
Modern exploration seismology acquires data that depend on four spatial variables and time. Each recorded seismogram belongs to a source-receiver pair dened by their spatial coordinates. The distribution of source and receiver on the surface of the Earth is often irregular, however, and thus...
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Fall 2012
Seismic events can be characterized by its origin time, location and moment tensor. Fast estimations of these source parameters are important in areas of geophysics like earthquake seismology, and the monitoring of seismic activity produced by volcanoes, mining operations and hydraulic injections...