Now showing items 1-10 of 27
A View of Unconstrained Optimization
Finding the unconstrained minimizer of a function of more than one variable is an important problem with many practical applications, including data fitting, engineering design, and process control. In addition, techniques ...
A Global Convergence Theory for Arbitrary Norm Trust Region Methods for Nonlinear Equations
In this research we extend the Levenberg-Marquardt algorithm for approximating zeros of the nonlinear system F(x) = 0, where F is continuously differentiable from R^n to R^n. Instead of the l2-norm, arbitrary norms can ...
An Algorithmic Characterization of Antimatroids
In an article entitled "Optimal sequencing of a single machine subject to precedence constraints," E.L. Lawler presented a now classical minmax result for job scheduling. In essence, Lawler's proof demonstrated that the properties of partially ordered sets were sufficient to solve the posed scheduling problem. These properties are, in fact, common to a more general class of combinatorial structures known as antimatroids, which have recently received considerable attention in the literature. It is demonstrated that the properties of antimatroids are not only sufficient but necessary to solve the scheduling problem posed by Lawler, thus yielding an algorithmic characterization of antimatroids. Examples of problems solvable by the general result are provided....
Simultaneous Determination of Source Wavelet and Velocity Profile Using Impulsive Point-Source Reflections from a Layered Fluid
The determination of source signature is a major calibration problem in reflection seismology. This "deconvolution" problem is conventionally approached by way of statistical methods, by direct measurement, or by the ...
Deflated Krylov Subspace Methods for Nearly Singular Linear Systems
This paper concerns the use of Krylov subspace methods for the solution of nearly singular nonsymmetric linear systems. We show that the Incomplete Orthogonalization Methods (IOM) in conjunction with certain deflation ...
A Short Proof of the Truemper-Tseng Theorem on Max-Flow Min-Cut Matroids
Seymour has characterized the matroids satisfying the integral max-flow min-cut property with respect to a fixed element. Truemper and Tseng subsequently proved a decomposition theorem for this class, similar in spirit to ...
ønix: A Unix Emulator for VAX/VMS
Domain Decomposition and Mixed Finite Element Methods for Elliptic Problems
In this paper we describe the numerical solution of elliptic problems with nonconstant coefficients by domain decomposition methods based on a mixed formulation and mixed finite element approximations. Two families of ...
Domain Decomposition Algorithms for Linear Hyperbolic Equations
The use of parallel computers for solving partial differential equations is important in areas such as fluid dynamics, reservoir simulation, and structural analysis, where many of the problems of interest cannot be solved ...