Research on optimal control, stabilization and computational algorithms for aerospace applications

The research carried out in the areas of optimal control and estimation theory and its applications under this grant is reviewed. A listing of the 257 publications that document the research results is presented

Analytical investigation of laminar flow through expanding or contracting gaps with porous walls

AbstractLaminar, isothermal, incompressible and viscous flow in a rectangular domain bounded by two moving porous walls, which enable the fluid to enter or exit during successive expansions or contractions is investigated analytically using optimal homotopy asymptotic method (OHAM). OHAM is a powerful method for solving nonlinear problems without depending to the small parameter. The concept of this method is briefly introduced, and it׳s application for this problem is studied. Then, the results are compared with numerical results and the validity of these methods is shown. After this verification, we analyze the effects of some physical applicable parameters to show the efficiency of OHAM for this type of problems. Graphical results are presented to investigate the influence of the non-dimensional wall dilation rate (α) and permeation Reynolds number (Re) on the velocity, normal pressure distribution and wall shear stress. The present problem for slowly expanding or contracting walls with weak permeability is a simple model for the transport of biological fluids through contracting or expanding vessels

Hierarchical control and decomposition of decentralized linear stochastic systems

Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.Vita.Bibliography: leaves 206-211.by Douglas P. Looze.Ph.D

A Recursive Algorithm for Mixture of Densities Estimation

In the framework of the so-called extended linear sigma model (eLSM), we include a pseudoscalar glueball with a mass of 2.6 GeV (as predicted by Lattice-QCD simulations) and we compute the two- and three-body decays into scalar and pseudoscalar mesons. This study is relevant for the future PANDA experiment at the FAIR facility. As a second step, we extend the eLSM by including the charm quark according to the global U(4)R × U(4)L chiral symmetry. We compute the masses, weak decay constants and strong decay widths of open charmed mesons. The precise description of the decays of open charmed states is important for the CBM experiment at FAIR

A survey on numerical methods for unconstrained optimization problems.

by Chung Shun Shing.Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.Includes bibliographical references (leaves 158-170).Abstracts in English and Chinese.List of Figures --- p.xChapter 1 --- Introduction --- p.1Chapter 1.1 --- Background and Historical Development --- p.1Chapter 1.2 --- Practical Problems --- p.3Chapter 1.2.1 --- Statistics --- p.3Chapter 1.2.2 --- Aerodynamics --- p.4Chapter 1.2.3 --- Factory Allocation Problem --- p.5Chapter 1.2.4 --- Parameter Problem --- p.5Chapter 1.2.5 --- Chemical Engineering --- p.5Chapter 1.2.6 --- Operational Research --- p.6Chapter 1.2.7 --- Economics --- p.6Chapter 1.3 --- Mathematical Models for Optimization Problems --- p.6Chapter 1.4 --- Unconstrained Optimization Techniques --- p.8Chapter 1.4.1 --- Direct Method - Differential Calculus --- p.8Chapter 1.4.2 --- Iterative Methods --- p.10Chapter 1.5 --- Main Objectives of the Thesis --- p.11Chapter 2 --- Basic Concepts in Optimizations of Smooth Func- tions --- p.14Chapter 2.1 --- Notation --- p.14Chapter 2.2 --- Different Types of Minimizer --- p.16Chapter 2.3 --- Necessary and Sufficient Conditions for Optimality --- p.18Chapter 2.4 --- Quadratic Functions --- p.22Chapter 2.5 --- Convex Functions --- p.24Chapter 2.6 --- "Existence, Uniqueness and Stability of a Minimum" --- p.29Chapter 2.6.1 --- Existence of a Minimum --- p.29Chapter 2.6.2 --- Uniqueness of a Minimum --- p.30Chapter 2.6.3 --- Stability of a Minimum --- p.31Chapter 2.7 --- Types of Convergence --- p.34Chapter 2.8 --- Minimization of Functionals --- p.35Chapter 3 --- Steepest Descent Method --- p.37Chapter 3.1 --- Background --- p.37Chapter 3.2 --- Line Search Method and the Armijo Rule --- p.39Chapter 3.3 --- Steplength Control with Polynomial Models --- p.43Chapter 3.3.1 --- Quadratic Polynomial Model --- p.43Chapter 3.3.2 --- Safeguarding --- p.45Chapter 3.3.3 --- Cubic Polynomial Model --- p.46Chapter 3.3.4 --- General Line Search Strategy --- p.49Chapter 3.3.5 --- Algorithm of Steepest Descent Method --- p.51Chapter 3.4 --- Advantages of the Armijo Rule --- p.54Chapter 3.5 --- Convergence Analysis --- p.56Chapter 4 --- Iterative Methods Using Second Derivatives --- p.63Chapter 4.1 --- Background --- p.63Chapter 4.2 --- Newton's Method --- p.64Chapter 4.2.1 --- Basic Concepts --- p.64Chapter 4.2.2 --- Convergence Analysis of Newton's Method --- p.65Chapter 4.2.3 --- Newton's Method with Steplength --- p.69Chapter 4.2.4 --- Convergence Analysis of Newton's Method with Step-length --- p.70Chapter 4.3 --- Greenstadt's Method --- p.72Chapter 4.4 --- Marquardt-Levenberg Method --- p.74Chapter 4.5 --- Fiacco and McComick Method --- p.76Chapter 4.6 --- Matthews and Davies Method --- p.79Chapter 4.7 --- Numerically Stable Modified Newton's Method --- p.80Chapter 4.8 --- The Role of the Second Derivative Methods --- p.89Chapter 5 --- Multi-step Methods --- p.92Chapter 5.1 --- Background --- p.93Chapter 5.2 --- Heavy Ball Method --- p.94Chapter 5.3 --- Conjugate Gradient Method --- p.99Chapter 5.3.1 --- Some Types of Conjugate Gradient Method --- p.99Chapter 5.3.2 --- Convergence Analysis of Conjugate Gradient Method --- p.108Chapter 5.4 --- Methods of Variable Metric and Methods of Conju- gate Directions --- p.111Chapter 5.5 --- Other Approaches for Constructing the First-order Methods --- p.116Chapter 6 --- Quasi-Newton Methods --- p.121Chapter 6.1 --- Disadvantages of Newton's Method --- p.122Chapter 6.2 --- General Idea of Quasi-Newton Method --- p.124Chapter 6.2.1 --- Quasi-Newton Methods --- p.124Chapter 6.2.2 --- Convergence of Quasi-Newton Methods --- p.129Chapter 6.3 --- Properties of Quasi-Newton Methods --- p.131Chapter 6.4 --- Some Particular Algorithms for Quasi-Newton Methods --- p.137Chapter 6.4.1 --- Single-Rank Algorithms --- p.137Chapter 6.4.2 --- Double-Rank Algorithms --- p.144Chapter 6.4.3 --- Other Applications --- p.149Chapter 6.5 --- Conclusion --- p.152Chapter 7 --- Choice of Methods in Optimization Problems --- p.154Chapter 7.1 --- Choice of Methods --- p.154Chapter 7.2 --- Conclusion --- p.157Bibliography --- p.15

NASA scientific and technical publications: A catalog of special publications, reference publications, conference publications, and technical papers, 1989

This catalog lists 190 citations of all NASA Special Publications, NASA Reference Publications, NASA Conference Publications, and NASA Technical Papers that were entered into the NASA scientific and technical information database during accession year 1989. The entries are grouped by subject category. Indexes of subject terms, personal authors, and NASA report numbers are provided