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We explore the use of preconditioned inversion in the reflection angle domain rather than migration to improve imaging in complex media. We use a wave-equation method to create reflection angle domain common image gathers and we apply steering filter preconditioning to smooth along the reflection angles. This improves the common image gathers. The improved… (More)

- Olav Lindtjorn, Robert G. Clapp, Oliver Pell, Haohuan Fu, Michael J. Flynn, Oskar Mencer
- IEEE Micro
- 2011

......Modeling and computation are taking an unprecedented role in the search for, and the extraction of, energy sources like oil and gas. The oil and gas industry already uses high-performance computing (HPC), but it’s still unclear how conventional HPC technologies can meet the demands of tomorrow’s algorithms. In this article, we describe the… (More)

Missing data interpolation problems can be conveniently preconditioned by recursive inverse filtering. A helix transform allows us to implement this idea in the multidimensional case. We show with examples that helix preconditioning can give a magnitude-order speedup in comparison with the older methods.

- K. Keeton, Robert G. Clapp, Abhilasha Nanda
- Computer
- 2003

these studies have generated several points of common wisdom for OLTP workloads. The many concurrent users in these applications lead to higher multiprogramming levels and context switch rates. As a result, OLTP workloads spend a nonnegligible percentage of their execution time in the operating system. Typically short-lived, OLTP workload transactions… (More)

Most geophysical problem require some type of regularization. Unfortunately most regularization schemes produce “smeared” results that are often undesirable when applying other criteria (such as geologic feasibility). By forming regularization operators in terms of recursive steering filters, built from a priori information sources, we can efficiently guide… (More)

- Haohuan Fu, Robert G. Clapp
- FPGA
- 2011

Memory-related constraints (memory bandwidth, cache size) are nowadays the performance bottleneck of most computational applications. Especially in the scenario of multiple cores, the performance does not scale with the number of cores in many cases. In our work, we present our FPGA-based solution for the 3D Reverse Time Migration (RTM) algorithm. As the… (More)

Depth imaging techniques still face difficulties under the edges of salt bodies. Elf encountered such a problem in a 3-D survey in the North Sea where they hoped to image a reflector that lays beneath a salt body. Based on the 3-D data, Elf created 2-D synthetic model of the salt body and surrounding subsurface. By analyzing this synthetic model using… (More)

Building on the notions of time-variable filtering and the helix coordinate system, we develop software for filters that are smoothly variable in multiple dimensions. Multiscale prediction-error filters (PEFs) can estimate dips from recorded data and use the dip information to fill in unrecorded shot or receiver gathers. The data are typically divided into… (More)

- Robert G. Clapp
- 2002

The single solution approach has a couple of significant drawbacks. First, since leastsquares estimates invert for the minimum energy/variance solution, our models tend to have lower spatial frequency than the true model. Second, it does not provide information on model variability or provide error bars on the model estimate. Geostatisticians have both of… (More)

- Jesse Lomask, Robert G. Clapp

We distribute the modified normalized cuts image segmentation with random boundaries algorithm on a parallel network to track 3D salt boundaries. We identify two key steps of this algorithm for parallelization. Firstly, we parallelize the calculation of the weight matrix. Secondly, we parallelize the matrix-vector product of the eigenvector calculation.… (More)