Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

20000064063 Geophysical Observatory, Helsinki, Finland
On the Connectivity Properties of the Rho-Boundary of the Unit Ball
Tossavainen, Timo, Geophysical Observatory, Finland; 2000; ISSN 1239-6303; 45p; In English; Sponsored in part by Yrjo
Foundation
Report No.(s): Rept-123; ISBN 951-41-0868-X; Copyright; Avail: Issuing Activity
In recent years, conformal mappings of subdomains of the plane have been studied from many perspectives. In the case of
f : B squared (right arrow) R squared conformal, one approach is to think of the absolute value of f’ as a given ’density’ rho on
B squared and then characterize properties of f by giving conditions on rho. A little surprisingly, only two simple axioms on rho
are needed to recover a remarkable part of geometric function theory.
Derived from text
Boundaries; Conformal Mapping; Euclidean Geometry; Analysis (Mathematics)
20000064581 NASA Ames Research Center, Moffett Field, CA USA
A Posteriori Error Estimation for Finite Volume and Finite Element Approximations Using Broken Space Approximation
Barth, Timothy J., NASA Ames Research Center, USA; Larson, Mats G., Chalmers Univ. of Technology, Sweden; Welcome to
the NASA High Performance Computing and Communications Computational Aerosciences (CAS) Workshop 2000; February
2000; In English; See also 20000064579; No Copyright; Abstract Only; Available from CASI only as part of the entire parent
document
We consider a posteriori error estimates for finite volume and finite element methods on arbitrary meshes subject to prescribed
error functionals. Error estimates of this type are useful in a number of computational settings: (1) quantitative prediction of the
numerical solution error, (2) adaptive meshing, and (3) load balancing of work on parallel computing architectures. Our analysis
recasts the class of Godunov finite volumes schemes as a particular form of discontinuous Galerkin method utilizing broken space
approximation obtained via reconstruction of cell-averaged data. In this general framework, weighted residual error bounds are
readily obtained using duality arguments and Galerkin orthogonality. Additional consideration is given to issues such as nonlinearity,
efficiency, and the relationship to other existing methods. Numerical examples are given throughout the talk to demonstrate
the sharpness of the estimates and efficiency of the techniques. Additional information is contained in the original.
Author
Error Analysis; Errors; Estimates; Finite Element Method; Finite Volume Method; Parallel Processing (Computers)
20000064692 College of William and Mary, Dept. of Mathematics, Williamsburg, VA USA
Bell-Curve Based Evolutionary Strategies for Structural Optimization, 1 Aug. 1999 - 31 Jul. 2000
Kincaid, Rex K., College of William and Mary, USA; [2000]; 4p; In English
Contract(s)/Grant(s): NAG1-2077; No Copyright; Avail: CASI; A01, Hardcopy; A01, Microfiche
Evolutionary methods are exceedingly popular with practitioners of many fields; more so than perhaps any optimization tool
in existence. Historically Genetic Algorithms (GAs) led the way in practitioner popularity (Reeves 1997). However, in the last
ten years Evolutionary Strategies (ESs) and Evolutionary Programs (EPS) have gained a significant foothold (Glover 1998). One
partial explanation for this shift is the interest in using GAs to solve continuous optimization problems. The typical GA relies upon
a cumber-some binary representation of the design variables. An ES or EP, however, works directly with the real-valued design
variables. For detailed references on evolutionary methods in general and ES or EP in specific see Back (1996) and Dasgupta and
Michalesicz (1997). We call our evolutionary algorithm BCB (bell curve based) since it is based upon two normal distributions.
Derived from text
Design Analysis; Genetic Algorithms; Strategy
20000065674 Joint Inst. for Nuclear Research, Bogolyubov Lab. of Theoretical Physics, Dubna, USSR
Solution of the N=(0/2) superconformal f-Toda lattice
Deryagin, V. B.; Leznov, A. N.; Sorin, A. S.; Dec. 31, 1998; 20p; In English
Report No.(s): DE99-607978; JINR-E-2-98-49; No Copyright; Avail: Department of Energy Information Bridge
The general solution of the two-dimensional integrable generalization of the f-Toda chain with fixed ends is explicitly presented
in terms of matrix elements of various fundamental representations of the SL (n/n-1) supergroup. The dominant role of
the representation theory of graded Lie algebras in the problem of constructing integrable mappings and lattices is demonstrated.
NTIS
Lattices (Mathematics); Solution
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