| Wafer-Fused Orientation-Patterned GaAs |
13 FEB 2008 |
9 pages |
| Authors:
Jin Li; David B. Fenner; Krongtip Termkoa; Mark G. Allen; Peter F. Moulton; Candace Lynch; David F. Bliss; William D. Goodhue; MASSACHUSETTS UNIV LOWELL
|
 | The fabrication of thick orientation-patterned GaAs (OP-GaAs) films is reported using a two-step process where an OP-GaAs template with the desired crystal domain pattern was prepared by wafer fusion bonding and then a thick film was grown over the template by low pressure hydride vapor phase epitaxy (HVPE). The OP template was fabricated using molecular beam epitaxy (MBE) followed by thermocompression wafer fusion, substrate removal, and lithographic patterning. On-axis (100) ... |
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| Computing the Observed Information Matrix for Dynamic Mixture Models |
25 SEP 2006 |
87 pages |
| Authors:
Michael J. Walsh; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
|
| The observed information matrix for an important class of finite mixture models, called dynamic mixture models, is derived in this report. Dynamic mixture models are useful probability models for random data originating from a number of distinct moving sources. The multiple-target tracking problem is one application of these models. For these models, the inverse of the observed information matrix is a consistent estimate of the error-covariance matrix for the mixture ... |
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| Polarimetric SAR Image Classification Employing Subaperture Polarimetric Analysis |
25 JUL 2005 |
4 pages |
| Authors:
T. L. Ainsworth; J. S. Lee; NAVAL RESEARCH LAB WASHINGTON DC REMOTE SENSING DIV
|
| Polarimetric SAR image classification remains an important research area. Various methods continue to be developed for specific applications. High-resolution polarimetric SAR systems and advances in computational and data storage capabilities have revived interest in novel polarimetric analysis techniques. Accordingly, subaperture analysis of polarimetric SAR data has received renewed attention. A central assumption of SAR image formation is that individual radar scatterers are stationary; they have no structure and provide a ... |
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| Investigation on Constrained Matrix Factorization for Hyperspectral Image Analysis |
25 JUL 2005 |
4 pages |
| Authors:
Qian Du; Ivica Kopriva; Harold Szu; MISSISSIPPI STATE UNIV MISSISSIPPI STATE DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| Matrix factorization is applied to unsupervised linear unmixing for hyperspectral imagery. The algorithm, called nonnegative matrix factorization, is used. It imposes a constraint on the non-negativity of the amplitudes of the recovered endmember spectral signatures as well as their fractional abundances. This ensures the recovery of physically meaningful endmembers and their abundances. This algorithm is further modified to include the sum-to-one constraint such that the sum of the fractional abundances ... |
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| Problems in Mathematical Statistics |
10 MAR 2005 |
9 pages |
| Authors:
N. R. Chaganty; OLD DOMINION UNIV RESEARCH FOUNDATION NORFOLK VA
|
| The primary goal of this project was to develop new statistical methods to meet the challenges of the evolving data analysis problems that the army encounters. These statistical methods also have numerous applications in biology, medicine and related sciences. Our research is focused on the following three important problems: (I) study mathematical details of the quasi-least squares method that we have developed for analyzing longitudinal and clustered data, (2) develop ... |
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| Adaptive Radar Detection of Extended Gaussian Targets |
20 DEC 2004 |
20 pages |
| Authors:
Giuseppe Ricci; Louis L. Scharf; LECCE UNIV (ITALY)
|
| We have addressed the derivation and the analysis of an adaptive decision scheme to detect possible extended targets modeled as Gaussian vectors known to belong to a given subspace; noise returns from the cells under test are modeled as independent and identically-distributed Gaussian vectors with one and the same covariance matrix; a set of secondary data free of signal components is also available; secondary data are Gaussian-distributed and share the ... |
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| Atomic Spectral Methods for Molecular Electronic Structure Calculations: Atomic-Pair Representations of Aggregate Hamiltonian Matrices (Postprint) |
15 NOV 2004 |
21 pages |
| Authors:
P. W> Langhoff; R. J. Hinde; J. D. Mills; J. A. Boatz; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| New methods which avoid the repeated constructions of aggregate Hamiltonian matrices over antisymmetric basis states generally required in conventional calculations of adiabatic potential energy surfaces are reported for ab initio studies of the structures, spectra, and chemical reactions of molecules and other forms of matter. A representational basis in the form of an outer spectral product of atomic eigenstates, employed in the absence of overall electron antisymmetry, is shown to ... |
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| Role of P13 Kinase Signaling Pathways in Polarity Determination of Human Mammary Epithelial Cells Grown in Three-Dimensional Extracellular Matrix |
SEP 2004 |
23 pages |
| Authors:
Hong Liu; CALIFORNIA UNIV BERKELEY LAWRENCE BERKELEY LAB
|
| Loss of tissue polarity and increased proliferation are the characteristic alterations of the breast tumor phenotype. To investigate these processes, we have used a three-dimensional (3D) culture system in which malignant human breast cells can be reverted to a normal phenotype. Exposure to inhibitors of phosphatidylinositol 3-kinase (PI3K) leads to decreased proliferation and restored tissue polarity. We show that Akt and Rac1 act as downstream effectors of PI3K and function ... |
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| Restoration of Wavelet-Compressed Images and Motion Imagery |
JAN 2004 |
68 pages |
| Authors:
Mark A. Robertson; AIR FORCE RESEARCH LAB ROME NY INFORMATION DIRECTORATE
|
| This technical report investigates the characteristics of compression noise in images and motion imagery compressed by scalar quantization of the data's two- or three-dimensional wavelet transform coefficients. Such quantization noise is both experimentally and theoretically shown to be spatially varying in the pixel domain, with statistical correlations between the errors at the pixel locations. A quantization noise covariance matrix is presented that can find use in general restoration scenarios where ... |
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| Short-Data-Record Adaptive Receivers for Rapidly Changing Communications Environments |
01 SEP 2003 |
112 pages |
| Authors:
Stella N. Batalama; Dimitris A. Pados; STATE UNIV OF NEW YORK AT BUFFALO AMHERST
|
| We defined and pursued a novel line of research that lies in a multidisciplinary intersection of Estimation Theory, Communications Theory, and Mean-Square optimum linear filtering. Consider an arbitrary input signal vector space and a given information bearing signal vector to be protected or recovered in the presence of multiuser or other forms of heavy interference. Based strictly on statistical conditional optimization principles, we developed an iterative algorithm that starts from ... |
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| A Computational Model for Sound Field Absorption by Acoustic Arrays (revision 6) |
24 JUL 2001 |
20 pages |
| Authors:
H. T. Banks; D. G. Cole; K. M. Furati; K. Ito; G. A. Pinter; NORTH CAROLINA STATE UNIV AT RALEIGH CENTER FOR RESEARCH IN SCIENTIFIC COMPUTATION
|
| In this paper, the authors discuss the sound absorption property of arrays of micro-acoustic actuators at a control surface. They use the wave equation over the half plane for the velocity potential with a boundary dissipation by a proportional pressure feedback law along the half plane boundary. The feedback gain over the array is described by a distributed shape function. They develop a computational method based on the Fourier transform ... |
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| On the Boundary Over Distance Preconditioner for Radial Basis Function Interpolation |
JUL 2001 |
|
| Authors:
C. T. Mouat; R. K. Beatson; CANTERBURY UNIV CHRISTCHURCH (NEW ZEALAND) DEPT OF MATHEMATICS AND STATISTICS
|
 | In this paper we consider the boundary over distance preconditioner for radial basis function interpolation problems. We give both theoretical and numerical results indicating that it performs extremely well. |
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| Generalised Gauss-Markov Regression |
JUL 2001 |
|
| Authors:
Alistair B. Forbes; Peter M. Harris; Ian M. Smith; NATIONAL PHYSICAL LAB TEDDINGTON (UNITED KINGDOM)
|
| Experimental data analysis is an key activity in metrology, the science of measurement. It involves developing a mathematical model of the physical system in terms of mathematical equations involving parameters that describe all the relevant aspects of the system. The model specifies how the system is expected to respond to input data and the nature of the uncertainties in the inputs. Given measurement data, estimates of the model parameters are ... |
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| Fixed- and Free-Knot Univariate Least-Squares Data Approximation by Polynomial Splines |
JUL 2001 |
|
| Authors:
Maurice Cox; Peter Harris; Paul Kenward; NATIONAL PHYSICAL LAB TEDDINGTON (UNITED KINGDOM)
|
| Fixed- and free-knot least-squares data approximation by polynomial splines is considered. Classes of knot-placement algorithms are discussed. A practical example of knot placement is presented, and future possibilities in free-knot spline approximation are addressed. |
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| A Wavelet-Based Preconditioning Method for Dense Matrices with Block Structure |
JUL 2001 |
|
| Authors:
Judith M. Ford; Ke Chen; LIVERPOOL UNIV (UNITED KINGDOM) DEPT OF MATHEMATICAL SCIENCES
|
| In recent years application of a discrete wavelet transform (DWT) has become an established tool for the design of preconditioners for smooth, dense matrices, such as those that arise in the solution of certain integral equations. In this paper we consider the higher dimensional case, where the matrix A is not itself smooth, but has a smooth block structure. To precondition such matrices, we use repeated application of a level ... |
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| How Many Holes Can Locally Linearly Independent Refinable Function Vectors Have? |
JUL 2001 |
|
| Authors:
Gerlind Plonka; DUISBURG UNIV (GERMANY) INST OF MATHEMATICS
|
| In this paper we consider the support properties of locally linearly independent refinable function vectors Phi. We propose an algorithm for computing the global support of the components of Phi. Further, for Phi we investigate the supports, especially the possibility of holes of refinable function vectors if local linear independence is assumed. Finally, we give some necessary conditions for local linear independence in terms of rank conditions for special matrices ... |
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| An Automatic Control Point Choice in Algebraic Numerical Grid Generation |
JUL 2001 |
|
| Authors:
C. Conti; R. Morandi; D. Scaramelli; FLORENCE UNIV (ITALY) DEPT OF ENERGETICA
|
| A strategy to construct a grid conforming to the boundaries of a prescribed domain by using transfinite interpolation methods is discussed. A transfinite interpolation procedure is combined with a B-spline tensor product scheme defined by using suitable control points. Their choice is performed by taking into account a quality measure parameter based on the condition number of matrices linked to the covariant metric tensors. |
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| Geometrical Symmetry in Symmetric Galerkin BEM |
JUL 2001 |
|
| Authors:
Alessandra Aimi; Mauro Diligenti; PARMA UNIV (ITALY) DIPARTIMENTO DI MATEMATICA
|
| We consider a symmetric boundary integral formulation associated with a mixed boundary value problem defined on a domain Omega is an element of the set of real numbers(2) with piecewise smooth boundary Gamma. We assume that Omega is mapped onto itself by a finite group G of congruences having at least two distinct elements. Hence, we can decompose the related symmetric Galerkin BEM problem into independent subproblems of reduced dimension ... |
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| Systems of Delay Equations with Small Solutions: A Numerical Approach |
JUL 2001 |
|
| Authors:
Neville J. Ford; Patricia M. Lumb; CHESTER COLL (UNITED KINGDOM)
|
| We consider systems of delay differential equations. We investigate whether a numerical method can be used to determine whether or not the equation has so-called small solutions. Our work builds on recent analysis and experimental work completed in the scalar case and we are able to conclude that at least when A is a suitable periodic matrix one can predict small solutions by using a numerical approximation scheme of fixed ... |
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| Interference Estimation and Mitigation for STAP Using the Two- Dimensional Wold Decomposition Parametric Model |
14 MAR 2001 |
19 pages |
| Authors:
Joseph M. Francos; Wenyin Fu; Arye Nehorai; ILLINOIS UNIV AT CHICAGO CIRCLE DEPT OFELECTRICAL ENGINEERING AND COMPUTER SCIENCE
|
| The goal of space-time adaptive processing (STAP) is to manipulate the available data to achieve high gain at the target angle and Doppler and maximal mitigation along both the jamming and clutter lines. Because the interference covariance matrix is unknown a priori, it is typically estimated using sample covariances obtained from averaging over a few range gates. The authors propose a new approach for parametric modeling and estimation of STAP ... |
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| Parametric Filters for Non-Stationary Interference Mitigation in Airborne Radars |
14 MAR 2001 |
7 pages |
| Authors:
Peter Parker; A. L. Swindlehurst; BRIGHAM YOUNG UNIV PROVO UT DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| Multichannel parametric filters are currently being studied as a means of reducing the dimension of Space-Time Adaptive Processing (STAP) algorithms for interference rejection in airborne pulsed-Doppler radar systems. These filters are attractive to use due to the low computational cost associated with their implementation as well as their near-optimal performance with a small amount of training data for a stationary environment. However, such filters do not perform well in certain ... |
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| Space-Time Adaptive FIR Filtering with Staggered PRI |
14 MAR 2001 |
|
| Authors:
R. Klemm; RESEARCH ESTABLISHMENT FOR APPLIED SCIENCES WACHTBERG- WERTHHOVEN (GERMANY)
|
| Space-time least squares far infrared radiation (FIR) filters have shown excellent clutter rejection performance at extremely low computational loads, allowing ground moving target indication (GMTI) to be carried out in real-time. Staggering the pulse repetition interval (PRI) is an appropriate way of avoiding Doppler ambiguities and blind velocities. Fully adaptive space-time processors can cope well with staggered echo data. FIR filtering techniques are based on constant PRI and, therefore, will ... |
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| Covariance Matrix Filtering for ABF With Moving Interference |
01 MAR 2001 |
12 pages |
| Authors:
B. K. Newhall; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
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| The Combinatorics of Cache Misses During Matrix Multiplication |
16 MAR 2000 |
39 pages |
| Authors:
Philip J. Hanlon; Dean Chung; Siddhartha Chatterjee; Daniel Genius; Alivn R. Lebeck; Erin Parker; MICHIGAN UNIV ANN ARBOR DEPT OF MATHEMATICS
|
| In this paper we construct an analytic model of cache misses during matrix multiplication. The analysis in this paper applies to square matrices of size 2m where the array layout function is given in terms of a function that interleaves the bits in the binary expansions of the row and column indices. We first analyze the number of cache misses for direct-mapped caches and then indicate how to extend this ... |
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| Symmetric Convolution. Using Unitary Transform Matrices: A New Approach to Image Reconstruction |
APR 1999 |
78 pages |
| Authors:
Thomas M. Foltz; AIR COMMAND AND STAFF COLL MAXWELL AFB AL
|
| The Air Force images space-borne objects from the ground with optical systems that suffer from the effects of atmospheric turbulence. Many image processing techniques exist to alleviate these effects, but they are computationally complex and require large amounts of processing time. A faster image processing system would greatly improve images of objects observed through the turbulent atmosphere and help national strategists glean higher quality intelligence on other nations space platforms. ... |
|
| T-matrix Approach to Array Modeling |
04 NOV 1998 |
24 pages |
| Authors:
Clyde L. Scandrett; Steven R. Baker; NAVAL POSTGRADUATE SCHOOL MONTEREY CA UNDERSEA WARFARE ACADEMIC GROUP
|
| The so-called T-matrix formulation for transducer array calculations is described from a theoretical standpoint. The methodology is then applied to an array problem whose solution can be found analytically, thereby producing a reference solution for comparing array calculations based upon FEM/BEM determined T-matrices. Three numerical codes have been tested for their accuracy in reproducing the exact T-matrix for a spherical shell. These in turn, are used to calculate the near ... |
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| Terrain-Relative Navigation for Autonomous Underwater Vehicles |
JUN 1997 |
|
| Authors:
Diane E. DiMassa; MASSACHUSETTS INST OF TECH CAMBRIDGE
|
| This thesis presents a terrain-relative navigation system for AUVs that does not require the deployment of acoustic beacons or other navigational aids, but instead depends on a supplied digital bathymetric map and the ability of the vehicle to image the seafloor. At each time step, a bathymetric profile is measured and compared to a local region of the supplied map using a mean absolute difference criterion. The region size is ... |
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| Control of Nonlinear Systems via State Feedback State-Dependent Riccati Equation Techniques |
JUN 97 |
299 pages |
| Authors:
Kelly D. Hammett; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
|
| Nonlinear regulation and nonlinear H-infinity control via state- dependent Riccati equation (SDRE) techniques are considered. Relationships between SDREs and Hamilton-Jacobi/Bellman inequalities/equations are examined, and a necessary condition for existence of solutions involving nonlinear stabilizability is derived. A single additional necessary criterion is given for the SDRE methods to yield the optimal control or guaranteed induced L2 gain properties. Pointwise stabilizability and detectability of factorizations prove necessary and sufficient, respectively, for ... |
|
| Invariant and Calibration-Free Methods in Scene Reconstruction and Object Recognition |
28 FEB 97 |
266 pages |
| Authors:
Richard I. Hartley; Joseph L. Mundy; GE CORPORATE RESEARCH AND DEVELOPMENT SCHENECTADY NY
|
| This is the final technical report for a DARPA project (#MDA 972-91- C-0053) on object recognition through the use of Geometric Invariants. It gives an extended account of the work that was done at GE-CRD and by certain collaborating researchers during the time of this project. The report considers the subjects of reconstruction of scenes from multiple views with a projective camera, and the recognition of objects from a single ... |
|
| A Partial Ordering of the Chordal Graphs |
07 FEB 97 |
15 pages |
| Authors:
Criag W. Rasmussen; Thomas Carroll; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF MATHEMATICS
|
| The chordal graphs have been well-studied because of their desirable algorithmic characteristics. Many problems that are intractable in the general case are solvable by fast algorithms in the chordal case. We show that the chordal graphs are partially ordered under edge set inclusion, and describe algorithms for bidirectional traversal of maximal chains in the corresponding cover graph. We also describe the embedding of several subclasses of the chordal graphs as ... |
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| Rank Ordering and Positive Bases in Pattern Search Algorithms |
DEC 96 |
27 pages |
| Authors:
Robert M. Lewis; Virginia Torczon; INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA
|
| We present two new classes of pattern search algorithms for unconstrained minimization: the rank ordered and the positive basis pattern search methods. These algorithms can nearly halve the worst case cost of an iteration compared to the classical pattern search algorithms. The rank ordered pattern search methods are based on a heuristic for approximating the direction of steepest descent while the positive basis pattern search methods are motivated by a ... |
|
| A Probabilistic Analysis of the Power of Arithmetic Filters |
SEP 96 |
31 pages |
| Authors:
Olivier Devillers; Franco Preparata; BROWN UNIV PROVIDENCE RI DEPT OF COMPUTER SCIENCE
|
| The assumption of real-number arithmetic, which is at the basis of conventional geometric algorithms, has been seriously challenged in recent years, since digital computers do not exhibit such capability. A geometric predicate usually consists of evaluating the sign of some algebraic expression. In most cases, rounded computations yield a reliable result, but sometimes rounded arithmetic introduces errors which may invalidate the algorithms. The rounded arithmetic may produce an incorrect result ... |
|
| Sample Selection for Covariance Estimation in Practical Airborne Environments |
SEP 96 |
13 pages |
| Authors:
William L. Melvin; ROME LAB ROME NY
|
| In this technical memorandum, a significant observation on a fundamental limitation to space-time adaptive processing in practical airborne environments is briefly discussed. This observation is a result of extensive analysis of measured airborne data from the Multichannel Airborne Radar Measurements (MCARMS) program. In particular, the problem of nonhomogeneous data and its impact on the estimation of the interference covariance matrix, a critical operation in space-time adaptive processing, is considered. ... |
|
| Vibration Reduction of Marine Cable Systems Using Dynamic Absorbers |
JUN 96 |
|
| Authors:
James E. Tatera; MASSACHUSETTS INST OF TECH CAMBRIDGE
|
| An engineering approach to the design of an in-line dynamic absorber is presented using transfer matrix techniques for an infinitely long cable system. The natural frequencies of the system are determined and the properties of the installed damper are optimized to maximize the amount of energy absorbed. Numerical simulations show that the optimally tuned and damped in-line dynamic absorber will dissipate 50% of incident transverse vibration energy. A design methodology ... |
|
| Non-Linear Finite Element Analyses of Composite Shells by Total Lagrangian Decomposition with Application to the Aircraft Tire |
MAR 96 |
280 pages |
| Authors:
James M. Greer Jr; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
|
| A total Lagrangian finite element scheme for arbitrarily large displacements and rotations is applied to a wide range of shell geometries. The scheme decomposes the deformation into stretches and rigid-body rotations, examining the deformed state with respect to an orthogonal, rigidly translated and rotated triad located at the point of interest on the deformed structure. The Jaumann stresses and strains, which are resolved along the axes of this triad, are ... |
|
| Euler Angles and Quaternions in Six Degree of Freedom Simulations of Projectiles |
MAR 1996 |
75 pages |
| Authors:
Michael J. Amoruso; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ ARMAMENT ENGINEERING DIRECTORATE
|
| When developing simulations of aircraft, missiles or gun-launched projectiles, investigators require a coordinate frame in which to follow the motion. Newton's laws require an inertial (unaccelerated) frame. The earth is a convenient reference frame but is not inertial since the earth rotates. The earth may nonetheless be used, with Coriolis and centripetal accelerations included to account for the earth's rotation. However, the projectile is both translating and rotating. Thus it ... |
|
| Prediction of Hydrodynamic Coefficients Utilizing Geometric Considerations |
DEC 95 |
95 pages |
| Authors:
Eric P. Holmes; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| A parametric study of a body of revolution is conducted utilizing existing semi-empirical methods for the calculation of hydrodynamic coefficients. The geometry of the body is analyzed in non-dimensional length and volume parameters. The effects of varying the nose, mid-body, and base fractions of the body on the hydrodynamic coefficients are generated and illustrated graphically. Equations for the hydrodynamic coefficients are then determined from the non-dimensional parameters. The results can ... |
|
| A Comparison of Methods for Estimating RMS Error: A Brute Force" Approach Versus a Mathematically-Elegant Approach, as Applied to the Calculation of a Specific Retrieval Error for a Limb-Scanning Microwave |
DEC 95 |
82 pages |
| Authors:
Larry L. Johnson; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| The Millimeter-wave Atmospheric Sounder (MAS) is a high resolution limb- scanning microwave radiometer-spectrometer which has been flown aboard the Space Shuttle. The instrument was designed to sense the microwave emission from several upper atmospheric constituents, including water vapor and ozone. The resonant frequencies of water vapor and ozone are extremely close (183 and 184 GHz, |
|
| A Comparison of Flight Input Techniques for Parameter Estimation of Highly-Augmented Aircraft |
SEP 95 |
118 pages |
| Authors:
Russell J. Gates; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Parameter estimation is an inverse process in which stability derivatives are determined from time history flight data by matching the aircraft mathematical model's computed response with the measured response of the aircraft. Accurate parameter estimation depends mainly on instrumentation and input technique. Input technique is the focus of this thesis in which both classical inputs and optimal inputs were applied under the same flight conditions to the High Angle of ... |
|
| A Study of Helicopter Rotor Dynamics and Modeling Methods |
SEP 95 |
133 pages |
| Authors:
Daniel S. Hiatt; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The rotor system is the primary source of vibratory forces on a helicopter. Vibratory forces result from the rotor system response to dynamic and aerodynamic loading. This thesis discusses sources of excitation, and investigates rotor system modeling methods. Computer models based on finite element and Mykiestad methods are developed and compared for the free and forced vibration cases of a nniform rotor blade. The modeling assumptions and the effects of ... |
|
| The Multivariate Gram-Charlier Series Applied to Random Signal Detection |
14 JUL 95 |
39 pages |
| Authors:
V. J. Aidala; NAVAL UNDERSEA WARFARE CENTER NEWPORT DIV RI
|
| This report comprises two parts. The first part focuses on extending the well known Gram Charlier series expansion technique for univariate probability density functions to multivariate functions. The approach employed here is particularly attractive because it avoids explicit use of tensor analysis and multivariate Hermite polynomials. The desired expansion is accomplished via straightforward application of Kronecker products and matrix calculus formulae. The second part of this report addresses the problem ... |
|
| Stability Analysis of a 2-D Acoustic/Structure Model |
JUN 95 |
90 pages |
| Authors:
Joe M. Shehan; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Reliably modeling noise attenuation through interaction with vibrating boundary structures is fundamental to the formulation of effective active noise control systems. In this paper we investigate, through numerical approximation, uniform exponential stability of two systems which model the acoustic/structure interaction of an air-filled, rectangular cavity. The first model assumes dissipative boundary conditions along one side of the boundary, while the second assumes dissipative boundary conditions along all four sides of ... |
|
| Design of a Hover Mode Autopilot for the Phoenix Autonomous Underwater Vehicle |
JUN 95 |
120 pages |
| Authors:
Juan C. Gonzalez Jr; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The potential uses for autonomous underwater vehicles (AUV's) is gaining recognition by organizations world wide. As such, continuous research toward improving existing vehicles by seeking new designs and increasing efficiency is being funded by organizations that serve to benefit from the new technology. Some examples for which AUV's may be used include mine countermeasures, submerged structural repair or destruction, search and rescue, biological study, ocean floor and coastal survey. The ... |
|
| Optimization of Linearly Constrained Indefinite Functions |
09 MAY 95 |
85 pages |
| Authors:
Wesley A. Hildebrandt; NAVAL ACADEMY ANNAPOLIS MD
|
| Global optimization is the process of finding a best solution among many possible solutions to a problem involving the minimization or maximization of some desired "cost" function. In general, many problems arising from practical applications can be formulated using both an objective function to be optimized (cost, profit, etc.) and a set of restrictions on the allowed solutions. In some cases this objective function may be linear, in which case ... |
|
| Numerical Methods for Determining Performance Limits of Linear Control |
31 MAR 95 |
6 pages |
| Authors:
Stephen P. Boyd; STANFORD UNIV CA
|
| During this contract, the research has focused on a related but different topic: analysis of nonlinear and/or time-varying systems using quadratic Lyapunov functions and convex optimization. Most importantly, these methods extend to state feedback synthesis for nonlinear, time-varying, and uncertain systems, and so should prove extremely useful in many industrial control problems. (AN) |
|
| Massively Parallel Iterative Methods: Multiscale Preconditioners and Implicit Methods |
22 MAR 95 |
8 pages |
| Authors:
Tony F. Chan; CALIFORNIA UNIV LOS ANGELES DEPT OF MATHEMATICS
|
| Nonlinear and linear systems of equations often arise in scientific computation, for example in implicit methods in Computational Fluid Dynamics (CFD). It is important to find cost-effective and accurate methods to solve such systems. Iterative methods are among those widely used, especially for 3D problems. In this project, we consider iterative methods which are especially suited to massively parallel architectures. To accelerate convergence of these iterative methods, preconditioners are often ... |
|
| Investigation of Ground Target Detection Methods in Fully Polarimetric Wide Angle Synthetic Aperture Radar Images |
MAR 95 |
177 pages |
| Authors:
Wayne B. Laggan; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| Target detection is a high priority of the Air Force for the purpose of reconnaissance and bombardment. This research investigates and develops methods to distinguish ground targets from clutter (i.e. foliage, landscape etc. ) in Wide Angle Synthetic Aperture Radar (WASAR) images. WASAR uses multiple aspect angle SAR images of the same target scene. The WASAR data was generated from a pre-release software package (XPATCH-ES) provided by the sponsor (WL- ... |
|
| Linear Algebraic Computation on Distributed Memory Parallel Machines |
SEP 94 |
4 pages |
| Authors:
Stanley C. Eisenstat; YALE UNIV NEW HAVEN CT DEPT OF COMPUTER SCIENCE
|
| The project entailed investigating several problems in the parallel solution of sparse systems of linear equations and eigenproblems, including: algorithms for factoring sparse matrices; techniques for the solution of sparse triangular systems; iterative methods for sparse systems, focusing mainly on preconditioning techniques for conjugate-direction methods; the solution of the symmetric tridiagonal eigenproblem. While this may seem to be an eclectic group of topics, there are, in fact, close relationships among ... |
|
| Wavelets, Signal Processing and Matrix Computations |
SEP 94 |
|
| Authors:
Bruce W. Suter; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
|
| Linear Estimation of Hyperspectral Mixed Pixel Components |
AUG 94 |
13 pages |
| Authors:
Edmundo Simental; Elisa Gonzalez; ARMY TOPOGRAPHIC ENGINEERING CENTER FORT BELVOIR VA
|
| This paper presents a method to determine end members along with their relative concentration in a hyperspectral mixed pixel. The method is modeled as a linear combination of the end members reflectance spectra and a library of spectral prototypes. This method was tested with 431-band, laboratory controlled, data sets. Indications are that this method can be extended to field data observations with a small number of end members and that ... |
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Reports by Keyword(s)
MATRICES(MATHEMATICS)
