| Limiting Impact Force Due to Yielding and Buckling of the Plates and Internal Structural Frame at the Bow of a Barge during Its Head-on Impact with a Bullnose or Cellular Structure |
Aug-2009 |
51 pages |
| Authors:
Robert M Ebeling; Terry W Warren; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS INFORMATION TECHNOLOGY LAB
|
 | This report presents a research study conducted to predict the impact forces that occur when a barge train impacts head-on with a circular concrete or concrete-filled structure. These structures are found at the end of lock approach walls as semicircles called bullnoses, as circular cells, and as mooring cells. This research was conducted using finite element analysis. A detailed finite element model of the bow of a jumbo hopper barge ... |
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| A Computational Study of Laminate Transparent Armor Impacted by FSP |
Jun-2009 |
14 pages |
| Authors:
C G Fountzoulas; J M Sands; B A Cheeseman; P G Dehmer; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| The current report reports on our efforts to simulate the ballistic impact of a fragment simulating projectile (FSP) into a Lexan 9034 polycarbonate (PC)- polymethyl-methacrylate (PMMA), which was a Plexiglas G manufactured by Atofina Chemicals, - Lexan 9034 Polycarbonate laminate system, with and without the presence of polyurethane adhesive, using the nonlinear analysis software AUTODYN. The simulation results, which included V50 measurements, were compared to the ballistic results from the ... |
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| Structural Optimization of Joined-Wing Beam Model with Bend-Twist Coupling Using Equivalent Static Loads |
Jun-2009 |
80 pages |
| Authors:
Nicholas S Green; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| This study is based on the merger of two separate theories to further the efficiency with which joined-wing structural models are designed. The first theory is Geometrically Exact Beam Theory (GEBT). GEBT is a small strain beam theory which is capable of accurately capturing the geometric bend-twist coupling in beam elements that are experiencing large global deformations. This is crucial to the joined-wing problem as it is geometrically nonlinear. The ... |
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| Path Force Control for Friction Stir Welding Processes (Preprint) |
Feb-2009 |
10 pages |
| Authors:
Prabhanjana Kalya; Xin Zhao; Robert G Landers; K Krishnamurthy; MISSOURI UNIV-ROLLA DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
|
| In Friction Stir Welding (FSW) processes, force control can be used to achieve good welding quality. This paper presents the systematic design and implementation of a FSW path force controller. The path force is modeled as a nonlinear function of the FSW process parameters (i.e., plunge depth, tool traverse rate, and tool rotation speed). An equipment model, which includes a communication delay, is constructed to relate the commanded and measured ... |
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| Demonstration Project Relating to Stress Analysis of SWAGE-Autofrettaged and Re-Autofrettaged Gun Tubes |
23 MAY 2008 |
7 pages |
| Authors:
Anthony P. Parker; PARKER (ANTHONY P) EAST SUSSEX (ENGLAND)
|
| The principal investigator (APP), worked for a total of two weeks at Benet Research Laboratory, Watervliet, NY, using results from a dummy swage autofrettage FEA stress analysis in a non-linear stress analysis of the post heat treatment hydraulic re-autofrettage of a swaged tube. APP collaborated with Benet staff in: (a) Predicting permanent OD strains for a re-autofrettaged gun tube manufactured from HB7 steel. and (b) Devising material modeling procedures for ... |
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| Sensitivity Analysis and Computation for Partial Differential Equations |
14 MAR 2008 |
13 pages |
| Authors:
Lisa G. Davis; MONTANA STATE UNIV BOZEMAN DEPT OF MATHEMATICAL SCIENCES
|
| The development of practical numerical methods for simulation of partial differential equations leads to problems of convergence, accuracy and efficiency. Verification of a computational algorithm consists in part of establishing a convergence theory for the discretized equations. It is well known that the long time behavior of a system may not be captured even by "convergent" approximating methods and additional requirements must be placed on the scheme to ensure the ... |
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| Computational Study of Separation Control Using ZNMF Devices: Flow Physics and Scaling Laws |
26 FEB 2008 |
14 pages |
| Authors:
Rajat Mittal; GEORGE WASHINGTON UNIV WASHINGTON DC
|
| The primary objective of the proposed research was to gain a fundamental understanding of strategies, mechanisms, and scaling laws for successful control of separation using zern-net mass-flux (ZNMF) actuators. The key issue that was systematically studied was the optimal excitation frequencies in separated flows characterized by convective and/or global instabilities. The study was a complementary experimental/ numerical effort that capitalized on previous collaborations and was aimed at leveraging the respective ... |
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| Toxicity of the Cyclic Nitramine Energetic Material CL-20 to Aquatic Receptors |
OCT 2007 |
22 pages |
| Authors:
Mark V. Haley; John S. Anthony; Emily A. Davis; Carl W. Kurnas; Roman G. Kuperman; Ronald T. Checkai; EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD
|
| We investigated the effects of the cyclic nitramine energetic material CL-20 (2,4,6,8,10,1 2-hexanitro-2,4,6,8, 10,12- hexaazaisowurtzitane) on Ceriodaphnia dubia (water flea), Pimephales promelas (fathead minnow), and Selenastrum capricornutum (green single celled algae). We designed experiments to include two types of exposure: (1) direct amendments of CL-20 to test media, and (2) aquatic elutriates from Sassafras Sandy Loam (SSL) soil amended with various concentrations of CL-20. Selected exposure routes that we simulated ... |
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| Development and Evaluation of Fusion Techniques |
OCT 2007 |
94 pages |
| Authors:
Mark G. Alford; Maria L. Scalzo; Adnan Bubalo; Eric C. Jones; AIR FORCE RESEARCH LAB ROME NY INFORMATION DIRECTORATE
|
| The purpose of this effort was to investigate and develop promising innovative technologies that hold promise for improvements in the Air Force target tracking and fusion capabilities. The problem statement is that Nonlinear Non-Gaussian Processes (NNGP) present a major challenge in all types of military problems. This is because the real-world is nonlinear and non-Gaussian, despite assumptions made in most conventional fusion algorithms. This in-house program addressed this problem by ... |
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| Polyarylenethioethersulfone Membranes for Fuel Cells (Postprint) |
SEP 2007 |
12 pages |
| Authors:
Stanley J. Rodrigues; Thomas L. Reitz; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| High performance, sulfonated polyarylenethioethersulfone (SPTES) polymers have been developed as membranes for fuel cells. These high molecular weight polymers synthesized by a polycondensation process have an aromatic backbone along with high sulfonic acid content that provides for their high conductivity and robust mechanical properties. Bulky phenyl-based end-capping agents are incorporated into the system to maintain high water stability and retain high proton conductivity. Films with good mechanical properties were obtained ... |
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| Signal Processing Fault Detection System |
13 JUL 2007 |
28 pages |
| Authors:
Derke R. Hughes; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A fault detection system designed to evaluate the structural integrity of a material employs an array of sensors disposed over the material being evaluated. The sensors detect vibrations in the material and the sensor signals are fed to a data processor. The processor employs a method to analyze the linear and nonlinear characteristics of the sensor signals and then determines whether to proceed with a linear signal processing analysis or ... |
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| Mathematics of Failures in Complex Systems: Characterization and Mitigation of Service Failures in Complex Dynamic Systems |
30 JUN 2007 |
142 pages |
| Authors:
Asok Ray; PENNSYLVANIA STATE UNIV UNIVERSITY PARK COLL OF ENGINEERING
|
| Objectives: The goal of this MURI project is to enhance dependability of complex engineering systems that include both human-operated and unmanned machinery. It focuses on pervasive fault tolerance based on the emerging information. The specific objective are: 1. Early detection of small anomalies in nonlinear and nonstationary dynamical systems. 2. Analysis and synthesis of robust decision and control systems to restrict the system behavior within desired specifications. 3. Development of ... |
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| Modeling and Control of State-Affine Probabilistic Systems for Atomic-Scale Dynamics |
JUN 2007 |
56 pages |
| Authors:
Martha A. Gallivan; GEORGIA INST OF TECH ATLANTA SCHOOL OF CHEMICAL ENGINEERING
|
| Under this research grant, the framework and tools were developed for model reduction of atomic-scale many body systems. The state-affine mathematical structure of the original and reduced order models enabled the implementation of control through dynamic programming and estimation through an extended Kalman filter. The state of the high-dimensional stochastic system is first quantified using a high-dimensional pair correlation function. This state is then reduced using linear and nonlinear principal ... |
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| Nonlinear Fault Detection, Isolation and Recovery Techniques for Unmanned Systems |
30 MAR 2007 |
238 pages |
| Authors:
K. Khorasani; CONCORDIA UNIV MONTREAL (QUEBEC) DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| In order to avoid adverse consequences due to failures, it is desirable to have an advanced failure detection and isolation (FDI) system that detects and identifies anomalies early to minimize the damage, and that can remedy as many failures as possible. In complex systems, fault diagnosis is typically accomplished using a hierarchical approach. In our proposed autonomous unmanned vehicle (UAV) system, fault diagnosis, isolation and recovery (FDIR) is accomplished by ... |
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| State Space Model for Autopilot Design of Aerospace Vehicles |
MAR 2007 |
|
| Authors:
Farhan A. Faruqi; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION EDINBURGH (AUSTRALIA) WEAPONS SYSTEMS DIV
|
 | This report is a follow on to the report given in DSTO-TN-0449 and considers the derivation of the mathematical model for aerospace vehicles and missile autopilots in state space form. The basic equations defining the airframe dynamics are non-linear, however, since the nonlinearities are structured (in the sense that the states are of quadratic form) a novel approach of expressing this non-linear dynamics in state space form is given. This ... |
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| The Chaos of Katrina |
MAR 2007 |
104 pages |
| Authors:
Jr Morris Gerald W.; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| This thesis presents a case study of federal logistics support during Hurricane Katrina disaster relief operations. Data from federal contracts covering the first 10 weeks of Katrina are used to measure federal logistics activity. The study investigates whether chaos theory, part of complexity science, can extract information from Katrina contracting data to help managers make better logistics decisions during disaster relief operations. The study uses three analytical techniques: embedding, fitting ... |
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| Constrained Estimation for GPS/Digital Map Integration (Postprint) |
01-Jan-2007 |
12 pages |
| Authors:
Erik Blasch; Thao Nguyen; Mikel Miller; Chun Yang; SIGTEM TECHNOLOGIES INC SAN MATEO CA
|
| Linear and nonlinear constrained estimation is investigated in this paper as an optimal method to integrate GPS fixes with digital maps so as to improve accuracy and reliability. In addition to emergency location and roadside assistance, the integration of GPS with digital maps becomes an increasingly popular application in automotives particularly for real-time routing, driving guidance, and street prompting. A position fix is obtained by a GPS receiver, which may ... |
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| A High Order WENO Scheme for a Hierarchical Size-Structured Model |
2007 |
18 pages |
| Authors:
Jun Shen; Chi-Wang Shu; Mengping Zhang; BROWN UNIV PROVIDENCE RI DIV OF APPLIED MATHEMATICS
|
| In this paper we develop a high order explicit finite difference weighted essentially non-oscillatory (WENO) scheme for solving a hierarchical size-structured population model with nonlinear growth, mortality and reproduction rates. The main technical complication is the existence of global terms in the coefficient and boundary condition for this model. We carefully design approximations to these global terms and boundary conditions to ensure high order accuracy. Comparing with the first order ... |
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| Observed Statistics of Extreme Waves |
DEC 2006 |
67 pages |
| Authors:
Anne M. Laird; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF OCEANOGRAPHY
|
| Amphibious landings and small boat operations are normally conducted only in benign wave conditions. An unexpected encounter with an isolated freak wave may damage equipment and prevent mission accomplishment. This study examines the occurrence of unusually large waves using data sets obtained with bottom mounted pressure sensors and wave buoys in the DUCK 94, SHOWEX, and SAX 04 experiments. All of the experiments include wave records from high energy events. ... |
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| Clutter Removal and Inversion of Eddy-Current Impedance Data (Postprint) |
DEC 2006 |
10 pages |
| Authors:
Harold A. Sabbagh; Elias H. Sabbagh; R. K. Murphy; John C. Aldrin; Jeremy S. Knopp; Eric Lindgren; VICTOR TECHNOLOGIES LLC BLOOMINGTON IN
|
| A wide variety of problems in computational electromagnetics have been successfully solved using a volume-integral approach along with conjugate-gradient methods. The volume integral algorithm is particularly well suited to the notion of model-based inversion of eddy-current impedance data in the arena of quantitative nondestructive evaluation (NDE). The first step in preparing data for inversion is to remove 'clutter,' which can originate in systematic measurement errors, or simply be a large ... |
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| Boussinesq Modeling of Alongshore Swash Zone Currents |
DEC 2006 |
20 pages |
| Authors:
Q. J. Chen; LOUISIANA STATE UNIV BATON ROUGE DEPT OF CIVIL AND ENVIRONMENTAL ENGINEERING
|
| The report documents the theoretical and numerical investigations on wave propagation over porous beds as well as on alongshore surf and swash currents. The study has been carried out in the framework of wave-resolving Boussinesq-type models. First, we have derived a new set of Boussinesq-type equations for nonlinear waves and surf-zone currents over a permeable beach (Chen 2006). A Stokes-type analysis and rational expansions were carried out to examine the ... |
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| Ecological Soil Screening Levels for Plants Exposed to Tnt: Supporting Range Sustainability for Training and Testing |
01-Nov-2006 |
5 pages |
| Authors:
Michael Simini; Ronald T Checkai; Jan E Kolakowski; Roman G Kuperman; Carlton T Phillips; Carl W Kumas; EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD
|
| Ecological Soil Screening Levels (Eco-SSL) are those screening concentrations of chemicals in soil that present an acceptable risk to ecological receptors. We investigated the ecotoxicity of TNT to the plant species alfalfa (Medicago sativa L.), Japanese millet (Echinochloa crusgalli L. (Beauv.)), and perennial ryegrass (Lolium perenne L.) in five natural soils: Sassafras sandy loam (SSL), Teller sandy loam (TSL), Richfield clay loam (RCL), Kirkland clay loam (KCL), and Webster clay ... |
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| Trajectory Control for Very Flexible Aircraft |
30 OCT 2006 |
47 pages |
| Authors:
Christopher M. Shearer; Cesnik E. Carlos; MICHIGAN UNIV ANN ARBOR
|
| This paper focuses on trajectory control of the 6-DOF body fixed reference frame located on a very flexible aircraft. The 6-DOF equations of motion of a reference point on the aircraft are coupled with the aeroelastic equations that govern the geometrically nonlinear structural response of the vehicle. A low-order strain-based nonlinear structural analysis coupled with unsteady finitestate potential flow aerodynamics form the basis for the aeroelastic model. The nonlinear beam ... |
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| Large Concentration-Dependent Nonlinear Optical Responses of Starburst Diphenylamino-fluorenocarbonyl Methano[60]Fullerence Pentaads |
OCT 2006 |
35 pages |
| Authors:
Hendry I. Elim; Wei Ji; Robinson Anandakathir; Long Y. Chiang; Rachel Jakubiak; Loon-Seng Tan; NATIONAL UNIV OF SINGAPORE DEPT OF PHYSICS
|
| We demonstrated an approach toward the design of starburst C60-keto-DPAF assembly by applying a combination of a starburst macromolecular configuration with C60 as the core center, which is encapsulated by multiple bulky groups leading to the increase of intermolecular separation and aggregation barrier. Molecular compositions of the resulting triad and pentads were clearly confirmed by MALDI-MS (positive ion) detection of protonated molecular mass ions. Both structural isomers, 3a and 3b ... |
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| Nonlinear Symplectic Attitude Estimation for Small Satellites |
AUG 2006 |
|
| Authors:
James M. Valpiani; Philip L. Palmer; SURREY UNIV GUILDFORD (UNITED KINGDOM)
|
| A novel method for efficient high-accuracy satellite attitude estimation is presented to address the increasing performance requirements of resource-constrained small satellites. Symplectic numerical methods are applied to the nonlinear estimation problem for Hamiltonian systems, leading to a new general solution that exactly preserves state probability density functions and conserves invariant properties of the dynamics when solving for the state estimate. This nonlinear Symplectic Filter is applied to a standard small ... |
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| Development of Novel Two-Photon Absorbing Chromophores |
AUG 2006 |
15 pages |
| Authors:
Thomas M. Cooper; James Heinrichs; Loon-Seng Tan; Augustine M. Urbas; Paul A. Fleitz; Joy E. Rogers; Jonathan E. Slagle; Daniel G. McLean; Richard L. Sutherland; Mark Brant; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| There has been much interest in the development of two-photon absorbing materials and many efforts to understand the nonlinear absorption properties of these dyes, but this area is still not well understood. A computational model has been developed in our lab to understand the nanosecond nonlinear absorption properties that incorporate all of the measured one-photon photophysical parameters of a class of materials called AFX. We have investigated the nonlinear and ... |
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| An Analysis of Nonlinear Elastic Deformations for a Homogeneous Beam at Varying Tip Loads and Pitch Angles |
JUN 2006 |
106 pages |
| Authors:
Robert J. McGraw; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| The Princeton beam experiments of 1975 were performed in hopes of producing viable data for beam nonlinear elastic deformation models in hopes of improving helicopter main beam designs. The recorded data, specifically for homogeneous beams of 7075 aluminum, have been referenced as a baseline for the past thirty years to validate numerous computer models and theories in an effort to build beams capable of withstanding aeroelastic, static, and dynamic loading. ... |
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| Toxicity of RDX, HMX, TNB, 2,4-DNT, and 2,6-DNT to the Earthworm, Eisenia Fetida, in a Sandy Loam Soil |
MAR 2006 |
49 pages |
| Authors:
Michael Simini; Ronald T. Checkai; Roman G. Kuperman; Carlton T. Phillips; Jan E. Kolakowski; Carl W. Kurnas; Geoffrey Sunahara; EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD
|
| The U.S. Environmental Protection Agency is developing Ecological Soil Screening Levels (Eco-SSLs) for ecological risk assessment of soil contaminants at Superfund sites. Insufficient information existed to generate Eco-SSLs for explosives and related materials in soil. The earthworm (Eisenia fetida) reproduction test was conducted in Sassafras sandy loam soil amended with hexahydro-1,3 ,5-trinitro-1,3 5-triazine (RDX), octahydro-1 3,5,7-tetranitro-1,3 ,5,7-tetrazocine (HMX), 2,4-dinitrotoluene (2,4-DNT), 2,6-dinitrotoluene (2,6-DNT), and 1,3,5-trinitrobenzene (TNB) to fill the data gaps. ... |
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| Integrated Sensing and Processing Digital Synapses |
03 JAN 2006 |
11 pages |
| Authors:
Ronald R. Coifman; Vladimir Rokhlin; Steven Zucker; Andreas Coppi; Frank Geschwind; YALE UNIV NEW HAVEN CT
|
| Over the duration of phase I of the ISP (01-Aug-2002 to 31-Jul-2005), we built two digitally controlled sensing systems and assembled a tabletop environment for testing and demonstration of massive data acquisition and handling. Components of the system are discussed. A variety of analytical tools for achieving the diffusion and low-dimensional paramaterizations have been developed. Examples given of results during the research in phase 1, and details of the research, ... |
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| Superconvergence of Discontinuous Galerkin Solutions for a Nonlinear Scalar Hyperbolic Problem |
2006 |
17 pages |
| Authors:
Slimane Adjerid; Thomas C. Massey; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
|
| In this paper, we study the superconvergence of the discontinuous Galerkin solutions for nonlinear hyperbolic partial differential equations. On the first inflow element we prove that the p-degree discontinuous finite element solution converges at Radau points with an O(h p+2) rate. We further show that the solution flux converges on average at O(h 2p+2)) on element outflow boundary when no reaction terms are present. Globally, we prove that the flux ... |
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| Velocity and Structure Estimation of a Moving Object Using a Moving Monocular Camera |
2006 |
10 pages |
| Authors:
V. K. Chitrakaran; D. M. Dawson; J. Chen; H. Kannan; CLEMSON UNIV SC DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| In this paper, we present the development of a vision-based estimator for simultaneous determination of velocity and structure of an object (i.e., the Euclidean position of its feature points) for the general case where both the object and the camera are moving relative to an inertial frame of reference. The velocity estimation itself requires no explicit kinematic model, while the adaptive structure estimator, synthesized utilizing Lyapunov design methods, is built ... |
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| A Lyapunov-Based Method for Estimation of Euclidean Position of Static Features Using a Single Camera |
2006 |
8 pages |
| Authors:
Vilas K. Chitrakaran; Darren M. Dawson; CLEMSON UNIV SC DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| In this paper, we present the design of an adaptive nonlinear algorithm for estimation of Euclidean position of features in a static environment in the field of view of a monocular camera. The development of the geometric model and camera motion kinematics is based on our previous work in [2]. This paper presents a new alternate approach to estimation of 3D coordinates of feature points that is simpler in mathematical ... |
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| Modeling, Stability, and Control of a Rotatable Tail on a Micro Air Vehicle |
DEC 2005 |
131 pages |
| Authors:
Travis J. Higgs; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| This research uses existing experimental wind tunnel data to develop a non-linear model that is used to characterize the stability of a flexible wing Micro Air Vehicle (MAV) with a rotatable tail. The experimental data are curve fit based on either angle of attack or angle of sideslip, and the coupled effect of tail rotation and tail deflection on the force and moment coefficients. Static optimization trims the input and ... |
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| Theoretical Modeling of Josephson Junctions for Digital Electronics |
29 NOV 2005 |
9 pages |
| Authors:
James K. Freericks; GEORGETOWN UNIV WASHINGTON DC DEPT OF PHYSICS
|
| This is the final technical report for James Freericks' ONR superconducting electronics grant for the period from 1999-2005. This work involved the development of computer modeling codes to describe Josephson junctions with barrier materials that are tuned close to the metal-insulator transition. The figure of merit can be determined as a function of different parameters, including the proximity to the metal-insulator transition, the thickness of the barrier, and the temperature. ... |
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| Dynamic Escape Routes for Naval Ships |
SEP 2005 |
121 pages |
| Authors:
Francisco J. Villalonga; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF OPERATIONS RESEARCH
|
| This thesis addresses the problem of optimal evacuation of a naval ship. We propose the use of a dynamic escape-route system which employs a signaling system to adapt the emergency egress process to the instigating contingency. The evacuation process is represented by a nonlinear network optimization model with an objective function that integrates two conflicting goals: the average evacuation time and the ship's integrity. The nonlinearity in the model results ... |
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| Multiobjective Optimization on Function Spaces: A Kolmogorov Approach |
JUL 2005 |
63 pages |
| Authors:
J. C. Allen; D. Acero; SPACE AND NAVAL WARFARE SYSTEMS CENTER SAN DIEGO CA
|
| This report makes explicit that the Kolmogorov Criterion can specialize with sufficient detail to yield concrete and computationally viable tests that identify solutions to difficult optimization problems. Specifically, the classical equal-ripple characterization of best polynomial approximation is generalized to nonlinear polynomial optimization, and then generalized again to multiobjective polynomial optimization. Thus, results in polynomial optimization stretching over this last century readily fit into a single framework and are illustrated with ... |
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| Adaptive Arrays and Tracking |
20 DEC 2004 |
38 pages |
| Authors:
Frederick E. Daum; RAYTHEON ELECTRONIC SYSTEMS SUDBURY MA
|
| Adaptive arrays and tracking share many concepts mathematical tools, practical issues, and algorithms. For example, ill-conditioning of the sample covariance matrix for adaptive arrays and ill-conditioning of the covariance matrix in a Kalman filter are both serious problems that can be mitigated by the same set of about a dozen methods, including Tychonoff regularization (called "diagonal loading" in adaptive arrays), factorization of the covariance matrix, using principal coordinates or approximately ... |
|
| Advanced Physiological Monitoring of FCS Soldiers |
DEC 2004 |
9 pages |
| Authors:
L. M. Hively; V. A. Protopopescu; OAK RIDGE NATIONAL LAB TN
|
| We quantify dynamical change in nonlinear time-serial data via dissimilarity measures between statistical distribution functions. These new measures are superior to traditional nonlinear measures and give robust and timely forewarning of normal-to-abnormal transitions in physiological regimes. These novel measures also provide rapid quantitative assessment of physiological change such as alertness, soldier readiness and bioagent exposure. |
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| Environmental Toxicity of the Explosives RDX and TNT in Soil to the Soil Invertebrate Folsomia candida |
DEC 2004 |
3 pages |
| Authors:
Carlton T. Phillips; Ronald T. Checkai; Roman G. Kuperman; Michael Simini; Jan E. Kolakowski; Carl W. Kurnas; EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD
|
| We investigated the toxicity of hexahydro-1,3,5- trinitro-1,3,5- triazine (RDX) and 2,4,6-trinitrotoluene (TNT) to the soil invertebrate Folsomia candida (Collembola) in five natural soils: Sassafras sandy loam (SSL), Teller sandy loam (TSL), Richfield clay loam (RCL), Kirkland clay loam (KCL), and Webster clay loam (WCL). According to the Ecological Soil Screening Level (Eco- SSL) criteria (USEPA 2003), relative bioavailability scores for organic chemicals in these soils were considered high for SSL ... |
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| Kernel-Based Anomaly Detection in Hyperspectral Imagery |
DEC 2004 |
9 pages |
| Authors:
Heesung Kwon; Nasser M. Nasrabadi; ARMY RESEARCH LAB ADELPHI MD
|
| In this paper we present a nonlinear version of the wellknown anomaly detection method referred to as the RXalgorithm. Extending this algorithm to a feature space associated with the original input space via a certain nonlinear mapping function can provide a nonlinear version of the RX-algorithm. This nonlinear RX-algorithm, referred to as the kernel RX-algorithm, is basically intractable mainly due to the high dimensionality of the feature space produced by ... |
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| Anisotropic Diffusion Despeckling for High Resolution SAR Images |
NOV 2004 |
7 pages |
| Authors:
Chen Xi; Wang Chao; Zhang Hong; Tang Yixian; BEIJING NORMAL UNIV (CHINA)
|
| The main purpose of this work is to perform a new denoising method based on a nonlinear anisotropic diffusion for the reducing of the multiplicative speckle in high resolution Synthetic Aperture Radar (SAR) images. In order to be applicable to the sampled data and reduce computing complexity, an efficient discretization scheme, e.g. additive operator splitting (AOS) scheme, is chosen here for the proposed approach. Examples are given comparing the new ... |
|
| Intelligent, Robust Control of Deteriorated Turbofan Engines via Linear Parameter Varying Quadratic Lyapunov Function Design |
NOV 2004 |
18 pages |
| Authors:
James A. Turso; Jonathan S. Litt; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN RESEARCH CENTER
|
| A method for accommodating engine deterioration via a scheduled Linear Parameter Varying Quadratic Lyapunov Function (LPVQLF)-Based controller is presented. The LPVQLF design methodology provides a means for developing unconditionally stable, robust control of Linear Parameter Varying (LPV) systems. The controller is scheduled on the Engine Deterioration Index, a function of estimated parameters that relate to engine health, and is computed using a multilayer feed forward neural network. Acceptable thrust response ... |
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| Internal Noise Prediction within Aircraft Cabin |
01 OCT 2004 |
|
| Authors:
Jean-Michael David; OFFICE NATIONAL D'ETUDES ET DE RECHERCHES AEROSPATIALES CHATILLON (FRANCE)
|
| For about two decades, Structural Dynamics and Coupled Systems Department of ONERA has developed, validated and applied different methods for modeling and predicting internal and external noise of complex structures in the low (LF), medium (MF) and high (HF) frequency ranges. These activities were initialized for sound radiated from submarine structures and then applied to aeronautic and space structures as helicopters, planes and launchers, for internal noise prediction. For the ... |
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| Design and Assessment of Ship Motion Control Systems with Advanced Numerical Simulation Tools |
OCT 2004 |
|
| Authors:
Woei-Min Lin; Kenneth M. Weems; Daniel A. Liut; SCIENCE APPLICATIONS INTERNATIONAL CORP ANNAPOLIS MD
|
| The accurate characterization of ship motions in different seaways is a basic requirement in the design of an effective ship motion control system. Traditionally, ship motion characteristics are obtained either by conducting model tests or by using numerical simulation based on simplified theories. However, model tests are typically expensive and time-consuming, and simplified theories may not be suitable for advanced hull forms such as wave piercers or multi-hulls and for ... |
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| Robust Adaptive Control of UCAVs |
30 SEP 2004 |
96 pages |
| Authors:
Yutaka Ikeda; James Ramsey; Eugene Lavretsky; Patrick McCormick; MCDONNELL DOUGLAS CORP ST LOUIS MO MANNED HYPERSONIC SPACE- CAPABLE VEHICLE TECHNOLOGIES DIV
|
| This report describes work performed to investigate adaptive nonlinear control for UCAVs. Specifc control techniques investigated were Internal Model Principle Nonliear Output Regulation for UCAV flight control desing and aero-servo-elastic filter deisgn; and Adaptive Inverse Control for electromagnetic actuator control design for UAVs and advaced missiles. Simulation results show good command following (or reference tracking) characteristic of the Internal Model Priciple Output Regulation technique for designs of flight control and ... |
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| Dissipation of Nonlinear Shallow Water Waves |
SEP 2004 |
10 pages |
| Authors:
Kacey L. Edwards; James M. Kaihatu; Jay Veeramony; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
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| Nonlinear frequency domain formulations of extended Boussinesq equations are studied. The new formulation retains the natural split between continuity and momentum equations, allowing for the dissipation term to be incorporated directly into the momentum equation. Additionally, due to the strong resemblance to the time domain equation, enacting a substantial computational savings. Lastly, a recently-published parameterization for the evolutionary behavior of the high wavenumber tail of surf zone spectra was tested ... |
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| Friction Test Specimens That Will Be Used to Measure Nonlinear Damping and Stiffness |
SEP 2004 |
17 pages |
| Authors:
Jerry H. Griffin; CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF MECHANICAL ENGINEERING
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| The funds received from the AFOSR were to be used to 1) purchase materials and machine friction test specimens and 2) refurbish a Brown and Sharpe Coordinate Measurement Machine (CMM). The specimens were used in an initially Carnegie Mellon University (CMU) supported and then US Navy supported research project titled, "Physical Models of Friction Constraint and The Effect of Friction on Bladed Disk Dynamics." For the first year, the graduate ... |
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| Dissipation of Wave Energy by Cohesive Sediments |
SEP 2004 |
9 pages |
| Authors:
James M. Kaihatu; Alexandru Sheremet; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
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| Wave energy dissipation by bottom muds is studied. A dissipation mechanism which contains explicit expressions of wavenumber modification due to a viscous bottom fluid is incorporated into a nonlinear wave shoaling model. This formulation allows a preliminary look at mud-induced energy decay without cumbersome root-finding numerics. Several cases of linear and nonlinear wave transformation over sloping and flat bottoms are run with the modified model. It is found that nonlinear ... |
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| Control of Mixing in Shear Flows |
18 AUG 2004 |
68 pages |
| Authors:
Andrazej Banaszuk; UNITED TECHNOLOGIES RESEARCH CENTER EAST HARTFORD CT
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| The objective of this research was to develop approach to control of mixing in shear flows and apply it to control of pattern factor and thermoacoustic instabilities in military aeroengines. A more general objective was to develop tools for modeling, analysis, and control design for unsteady non-equilibrium flow phenomena relevant to operation of aeroengines. |
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| Numerical Optimization of Multifunctional Components |
17 AUG 2004 |
9 pages |
| Authors:
Anthony T. Patera; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MECHANICAL ENGINEERING
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| Engineering components are increasingly complex in composition and structure and increasingly multifunctional. Indeed, it is only through complexity and multifunctionality that the defense industry can satisfy the stringent performance requirements associated with critical defense applications. However, these complex, multifunctional systems no longer admit intuitive analysis of trade-off considerations. Industries must pursue optimization, including optimal choice of material, configuration, and deployment to realize the potential of these new approaches. The essential ... |
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Reports by Keyword(s)
NONLINEAR ANALYSIS
