Now showing items 302-321 of 583

    • Joint Inversion Using the Convolutional Model 

      Winslow, Nathan W. (2000-04)
      A detailed imaging of an acoustic medium via a seismic experiment requires an accurate representation of the source. A joint source and reflectivity inversion may provide the means to obtain the desired detail. Joint ...
    • Karmarkar as a Classical Method 

      Morshedi, A.M.; Tapia, R.A. (1987-03)
      In this work we demonstrate that the Karmarkar algorithm for linear programs results from the classical approach of first transforming nonnegativity constraints into equality constraints by adding squared-slack variables ...
    • Kinematics of Shot-Geophone Migration 

      Stolk, Christiaan C.; de Hoop, Maarten V.; Symes, William W. (2005-04)
      Prestack migration methods based on data binning produce {\em kinematic artifacts}, i.e. coherent events not corresponding to actual reflectors, in the prestack image volume. Shot-geophone migration, on the other hand, ...
    • Krylov-Secant Methods for Solving Systems of Nonlinear Equations 

      Klíe, Héctor; Ramé, Marcelo; Wheeler, Mary F. (1995-09)
      We present a novel way of reusing the Krylov information generated by GMRES for solving the linear system arising within a Newton method. Our approach departs from the theory of secant preconditioners developed by Martinez ...
    • Large Time Asymptotics in Contaminant Transport in Porous Media 

      Dawson, C.N.; van Duijn, C.J.; Grundy, R.E. (1994-11)
      In this paper we derive large time solutions of the partial differential equations modelling contaminant transport in porous media for initial data with bounded support. While the main emphasis is on two space dimensions, ...
    • Large Time Solution of an Initial Value Problem for a Generalized Burgers Equation 

      Grundy, R.E.; Sachdev,P.L.; Dawson, Clint N. (1993-09)
    • Layered Velocity Inversion: A Model Problem from Reflection Seismology 

      Symes, William W. (1988-10)
      A simple model problem in exploration seismology requires that a depth-varying sound velocity distribution be estimated from reflected sound waves. For various physical reasons, these reflected signals or echoes have very ...
    • Least-Change Secant Update Methods with Inaccurate Secant Conditions 

      Dennis, J.E. Jr.; Walker, Homer F. (1983-11)
      In this paper, we investigate the role of the secant or quasi-Newton condition in the sparse Broyden or Schubert update method for solving systems of nonlinear equations whose Jacobians are either sparse, or can be ...
    • Levetiracetam mitigates doxorubicin-induced DNA and synaptic damage in neurons 

      Manchon, Jose Felix Moruno; Dabaghian, Yuri; Uzor, Ndidi-Ese; Kesler, Shelli R.; Wefel, Jeffrey S.; Tsvetkov, Andrey S. (2016)
      Neurotoxicity may occur in cancer patients and survivors during or after chemotherapy. Cognitive deficits associated with neurotoxicity can be subtle or disabling and frequently include disturbances in memory, attention, ...
    • Limited Memory Block Krylov Subspace Optimization for Computing Dominant Singular Value Decompositions 

      Liu, Xin; Wen, Zaiwen; Zhang, Yin (2013)
      In many data-intensive applications, the use of principal component analysis and other related techniques is ubiquitous for dimension reduction, data mining, or other transformational purposes. Such transformations often ...
    • Linear and Nonlinear Deconvolution Models 

      Olkin, Julia Ann (1986-04)
      This dissertation considers computational methods for solving linear and nonlinear least squares problems arising from deconvolution applications. For the linear problems we propose a new preconditioner to speed up the ...
    • Local Analysis of Inexact Quasi-Newton Methods 

      Eisenstat, Stanley C.; Steihaug, Trond (1982-05)
      Quasi-Newton methods are well known iterative methods for solving nonlinear problems. At each stage, a system of linear equations has to be solved. However, for large scale problems, solving the linear system of equations ...
    • Local and Superlinear Convergence for Truncated Projections Methods 

      Steihaug, Trond (1981-10)
      Least change secant updates can be obtained as the limit of iterated projections based on other secant updates. We show that these iterated projections can be terminated or truncated after any positive number of iterations ...
    • Local and Superlinear Convergence of Structured Secant Methods from the Convex Class 

      Martinez R., Hector J. (1988-01)
      In this paper we develop a unified theory for establishing the local and q-superlinear convergence of the secant methods from the convex class that take advantage of the structure present in the Hessian in constructing ...
    • Local Error Analysis of Discontinuous Galerkin Methods for Advection-Dominated Elliptic Linear-Quadratic Optimal Control Problems 

      Leykekhman, Dmitriy; Heinkenschloss, Matthias (2012-08-15)
      This paper analyzes the local properties of the symmetric interior penalty upwind discontinuous Galerkin (SIPG) method for the numerical solution of optimal control problems governed by linear reaction-advection-diffusion ...
    • Logarithmic Indicators and the Identification of Subgroups of Variables in Interior-Point Methods 

      El Bakry, A.S.; Tapia, R.A.; Zhang, Y. (1993-09)
      The identification of certain groups of variables in optimization problems is an important issue and can be used to computational advantage. In this paper new logarithmic indicators are introduced. It is demonstrated that ...
    • Loop Level Parallelization of a Seismic Inversion Code 

      Symes, William W.; Kern, Michael (1993-03)
      We present a parallel implementation of a seismic inversion code. Parallelism is exploited at the loop level within the finite difference modeling, as this is the most time consuming part of the code. We give details of ...
    • Lyapunov, Lanczos, and Inertia 

      Antoulas, A.C.; Sorensen, D.C. (2000-05)
      We present a new proof of the inertia result associated with Lyapunov equations. Furthermore we present a connection between the Lyapunov equation and the Lanczos process which is closely related to the Schwarz form of a ...
    • Mathematical Foundations of Reflected Wave Imaging 

      Symes, William W. (1990-02)
      The goal of these notes is to provide a consistent mathematical foundation for wave imaging - the production of images from measurements of reflected waves in heterogeneous media. This account is inspired mostly by reflection ...
    • A mathematical framework for inverse wave problems in heterogeneous media 

      Blazek, Kirk D.; Stolk, Christiaan; Symes, William W. (2013)
      This paper provides a theoretical foundation for some common formulations of inverse problems in wave propagation, based on hyperbolic systems of linear integro-differential equations with bounded and measurable coefficients. ...