| Analysis and Optimization of Elastic Materials |
10 DEC 95 |
14 pages |
| Authors:
Rouben Rostamian; William W. Hager; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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 | The objective of this research is to investigate the propagation of waves in stratified elastic media. The focus is on the design of elastic coatings which due to their layered nature deflect the incident energy of the waves and therefore can affect the reflectivity properties of solid surfaces in interesting ways. (MM) |
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| A Simple Model of Melt Fracture |
31 DEC 92 |
60 pages |
| Authors:
James Greenberg; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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| The PI produced an excellent explanation of the unpleasant shark- skinning observed in certain polymer extrusion processes. This work has been brought to the attention of researchers at Corning and Hoechst Celanese and Greenberg and Demay will work this summer with members of the Materials Sciences Center at the Ecole Nationale Superieure des Mines de Paris led by J.F. Agassant. One goal of this work is to see if the ... |
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| Higher Order Crossings |
SEP 92 |
10 pages |
| Authors:
Benjamin Kedem; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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| In the research on higher order crossings (HOC) they have solved some of the mathematical/statistical problems associated with a certain contraction mapping method for frequency detection and estimation in the presence of noise. They can now tell how to shrink the filters bandwidth to achieve almost sure convergence of the HOC sequence. The sample first order autocorrelation in filtered data is called a higher order correlation, or HOC again. Given ... |
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| Computational Aspects of Adaptive Dimensional Reduction for Nonlinear Boundary Value Problems |
24 FEB 90 |
10 pages |
| Authors:
Soren Jensen; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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| There has been increased interest recently in feed-back methods for reliable, robust, efficient computational methods in mechanics. We will outline the construction of such methods for a class of problems describing special (anti-plane shear) deformations of bars of rectangular or arched cross section. In particular, we will show how to reduce the dimension of the underlying problem adaptively . For brittle or linear materials, this method is adaptive (optimal in ... |
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| On Computing the Pressure by the p Version of the Finite Element Method for Stokes Problem |
15 FEB 90 |
24 pages |
| Authors:
Soren Jensen; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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| This paper introduces and analyzes two ways of extracting the hydrostatic pressure when solving Stokes problem using the p version of the finite element method. When one uses a local H superscript 1 projection, we show that optimal rates of convergence for the pressure approximation is achieved. When the pressure is not in H superscript, or the value of the pressure is only needed at a few points, one may ... |
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| A Feedback Extension to the Numerical Solution of Nonlinear Boundary Value Problems |
90 |
3 pages |
| Authors:
Soren Jensen; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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| A feed-back extension procedure is developed for the numerical solution of a class of nonlinear boundary value problems associated with anti- plane shear or Hencky's theory of plasticity. This extends previous results using dimensional reduction in energy-asymptotic format. (JHD) |
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| Request for a Computer Workstation and Video Peripherals (DURIP) |
28 NOV 89 |
2 pages |
| Authors:
James M. Greenberg; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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| Dr. Greenberg, acting as principal investigator under AFOSR Grant 89- 0101, entered into a contract with Ardent Computer Corporation of Sunnyvale, California to purchase a four processor Titan at a cost of 129,000. The department also purchased the video output devices outlined in the original proposal. This equipment has been invaluable to both the principal investigator and the other associate investigators on the original proposal; Dr. Greenberg has been engaged ... |
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| An H(mo) Interpolation Result |
14 NOV 89 |
8 pages |
| Authors:
S. Jensen; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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| This paper presents a proof of an interpolation results related to the approximation theory for higher order finite element or spectral methods when C superscript 1 (or higher) regularity is convenient for the finite dimensional subspaces. This can be a natural choice for example for Stokes problem, the biharmonic problem or higher order-plate- and shell models. We show that one gets the same intermediate spaces whether one 1) interpolates between ... |
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| Dimensional Reduction for Nonlinear Boundary Value Problems |
JUN 88 |
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| Authors:
Soren Jensen; Ivo Babuska; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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 | The theoretical and computational aspects of a numerical method for solving a class of strongly nonlinear boundary value problems with applications to nonlinear elastostatics are presented. The basic idea is solving the Galerkin system of equations in one dimension less than that of the original problem by choosing a priori a basis of functions in one of the variables. This choice of basis functions is made by ways of asymptotic ... |
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| Regular Inversion of the Divergence Operator with Dirichlet Boundary Conditions on a Polygon |
APR 87 |
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| Authors:
Douglas N. Arnold; L. R. Scott; Michael Vogelius; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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| Consider the existence of regular solutions to the boundary value problem div U = f on a plane polygonal domain Omega with the Dirichlet boundary condition U = g on del Omega. We formulate simultaneously necessary and sufficient conditions on f and g in order that a solution U exist in the Sobolev space W (over s+1 to p) (Omega). In addition to the obvious regularity and integral conditions these ... |
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| Optimal Adaptive Controllers for Unknown Markov Chains |
15 DEC 1980 |
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| Authors:
P. R. Kumar; Woei Lin; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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| Estimation for Discrete-Time Directional Processes. |
OCT 1975 |
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| Authors:
James Ting-Ho Lo; Linda R. Eshleman; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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| Error criteria, probability distributions, and optimal estimates on a sphere are discussed. Some properties of a special representation of a probability density on a sphere are studied. This representation has the desirable feature of being closed under the operation of taking conditional distributions. Facilitated with it, a finite-dimensional recursive scheme can be derived for a simple estimation model for directional processes. |
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| Representations of Multivariate Spline Functions and Applications. |
JUL 1974 |
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| Authors:
Marie-Jeanne Munteanu; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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| ;Contents: Representations of functions in several variables; Decomposition of linear differential problems; Generalized interpolation error estimates applications to differential equation. |
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| Multivariate Spline Functions. |
JUL 1974 |
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| Authors:
Marie-Jeanne Munteanu; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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| This report addresses various approaches to multidimensional splines including a partial survey of the literature. In the first section the combined case of interpolating and smoothing by the use of splines is presented. The second section presents a class of multivariate spline functions associated with a general partial differential operator defined on an appropriate Sobolev space. The third section addresses the tensor product of Ahlberg, Nilson, Walsh and the blending ... |
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| A Note on the Optimality of Generalized Interpolating Splines. |
MAR 1974 |
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| Authors:
Marie-Jeanne Munteau; MARYLAND UNIV BALTIMORE DEPT OF MATHEMATICS
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| The purpose of the note is to prove the optimality of generalized interpolating splines for operators. For this reason the author will generalize the well-known duality theorem for functionals to the case of linear operators. The idea of using duality theorems in order to prove the optimality of a certain approximation was inspired by Jean Meinguet's papers. (Modified author abstract) |
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