SCAN_59-01

59-01 APPLIED MATHEMATICS
Nov 22, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
System Design, Algorithm Development, and Verification for Optoacoustic Molecular Imaging of Protease Expression in Breast Cancer
Document ID:
20090038235
Report #:
AD-A506325
Available Online:
http://hdl.handle.net/100.2/ADA506325
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Modgil, Dimple
Published:
20090501
Source:
Chicago Univ. (Chicago, IL United States)
Pages:
45
Contract #:
W81XWH-08-1-0331
Abstract:
Optoacoustic tomography (OAT) is an emerging, hybrid technique that is non-invasive and uses non-ionizing radiation. No one has yet developed a molecular probe for early detection of proteases in breast cancer using OAT. Our group is developing a molecular probe and an optoacoustic imaging system to address this. During the first year of this project, we have implemented the code that simulates the ideal optoacoustic system. We have compared existing 2D algorithms in OAT with respect to contrast, resolution, noise and signal detectability. We also explored the effect of variable speed of sound and ultrasonic attenuation on image quality. We derived new techniques to address these physical effects that could cause image distortion and blurring.
Language:
English

Title:
Alternative Methods to Standby Gain Scheduling Following Air Data System Failure
Document ID:
20090038248
Report #:
AD-A506366, AFIT/GAE/ENY/09-S02
Available Online:
http://hdl.handle.net/100.2/ADA506366
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Coldsnow, Matthew W
Published:
20090901
Source:
Air Force Inst. of Tech. (Wright-Patterson AFB, OH United States)
Pages:
261
Contract #:
None
Abstract:
The United States Air Force has advanced fighter aircraft that lose the ability to operate in a large portion of their operating flight envelope when an air data system failure is experienced. These aircraft are reverted to a fixed set of standby-gains that limit their maneuverability, degrade handling qualities, and increase susceptibility to departure. The purpose of this research was to determine if three alternative methods of standby-gain-scheduling could provide robust control with minimal performance degradation despite the lack of air data. To accomplish this, three methods of standby-gain-scheduling were developed, integrated, and tested in the Infinity Cube simulator at the Air Force Research Laboratory/RBCD building. The first method improved upon an algorithm which used inertial data to estimate an aircraft's true velocity used to drive the gains in an F-16 controller. This algorithm was validated by post-processing high-fidelity simulator data and actual flight data. The second method simply used inertial velocities to drive the gains in an F-16 controller. The final method used a disturbance observer controller which controlled aircraft dynamics without the use of gain-scheduling. The results showed the potential for effective aircraft control with minimal performance degradation following an air data system failure. Potential benefits to this research include eliminating the need to make switch actuations to correctly schedule the standby-gains; improving aircraft performance when flying with standby-gains; allowing the pilot to continue with a combat mission instead of returning to base with an air data system failure; and helping contribute to the removal of Pitot tubes in an attempt to eliminate a failure mode and to reduce the radar cross section of an aerial vehicle.
Language:
English

Title:
Adiabatic Shock Capturing in Perfect Gas Hypersonic Flows
Document ID:
20090038730
Report #:
JSC-CN-18751
Sales Agency:
Other Sources Copyright
Author(s):
Kirk, Benjamin S. (NASA Johnson Space Center)
Published:
20090101
Source:
NASA Johnson Space Center (Houston, TX, United States)
Pages:
22
Contract #:
None
Abstract:
This paper considers the streamline-upwind Petrov/Galerkin (SUPG) method applied to the compressible Euler and Navier-Stokes equations in conservation-variable form. The spatial discretization, including a modified approach for interpolating the inviscid flux terms in the SUPG finite element formulation, is briefly reviewed. Of particular interest is the behavior of the shock capturing operator, which is required to regularize the scheme in the presence of strong, shock-induced gradients. A standard shock capturing operator which has been widely used in previous studies by several authors is presented and discussed. Specific modifications are then made to this standard operator which are designed to produce a more physically consistent discretization in the presence of strong shock waves. The actual implementation of the term in a finite dimensional approximation is also discussed. The behavior of the standard and modified scheme is then compared for several supersonic/hypersonic flows. The modified shock capturing operator is found to preserve enthalpy in the inviscid portion of the flowfield substantially better than the standard operator.
Language:
English
Notes:
To be published in the International Journal for Numerical Methods in Fluids, October 2009/John Wiles & Sons Ltd.

59-02 DATA PROCESSING
Nov 22, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Data Analysis for the LISA Pathfinder Mission
Document ID:
20090038186
Report #:
None
Sales Agency:
Other Sources No Copyright
Author(s):
Thorpe, James Ira (NASA Goddard Space Flight Center)
Published:
20090101
Source:
NASA Goddard Space Flight Center (Greenbelt, MD, United States)
Pages:
1
Contract #:
None
Abstract:
The LTP (LISA Technology Package) is the core part of the Laser Interferometer Space Antenna (LISA) Pathfinder mission. The main goal of the mission is to study the sources of any disturbances that perturb the motion of the freely-falling test masses from their geodesic trajectories as well as 10 test various technologies needed for LISA. The LTP experiment is designed as a sequence of experimental runs in which the performance of the instrument is studied and characterized under different operating conditions. In order to best optimize subsequent experimental runs, each run must be promptly analysed to ensure that the following ones make best use of the available knowledge of the instrument ' In order to do this, all analyses must be designed and tested in advance of the mission and have sufficient built-in flexibility to account for unexpected results or behaviour. To support this activity, a robust and flexible data analysis software package is also required. This poster presents two of the main components that make up the data analysis effort: the data analysis software and the mock-data challenges used to validate analysis procedures and experiment designs.
Language:
English
Notes:
American Astronomical Society meeting Washington, DC Jan. 2010

Title:
DoD Should Develop Deoxyribonucleic Acid Computing Technology
Document ID:
20090038366
Report #:
AD-A506515
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Hudson, Jr, J F
Published:
20080222
Source:
Marine Corps Development and Education Command (Quantico, VA United States)
Pages:
13
Contract #:
None
Abstract:
A Marine company has just arrived at its rally point. As they discuss the plan of attack, a sergeant notices that the plants around him are changing colors. He immediately yells gas, gas, gas and the Marines quickly put on gas masks and protective suits. Plants changing colors to warn a company that toxins are present? It cannot be true, but it is true, and this is one of the many capabilities that deoxyribonucleic acid (DNA) computing can provide the Department of Defense (DoD). Technological superiority must continue to be a characteristic of the U.S. military and one of the foundations of our national military strategy. DoD should develop DNA computing technology for the services because it protects classified information, enhances medical functions, and provides battlefield advantages.
Language:
English

60-01 DIGITAL AND ANALOG COMPUTERS
Nov 22, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Multi-Core Processor Memory Contention Benchmark Analysis Case Study
Document ID:
20090038666
Report #:
None
Available Online:
http://hdl.handle.net/2060/20090038666
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Simon, Tyler (Computer Sciences Corp.) McGalliard, James (General Services Administration)
Published:
20090101
Source:
Computer Sciences Corp. (Greenbelt, MD, United States)
Pages:
12
Contract #:
NNG08HZ01I
Abstract:
Multi-core processors dominate current mainframe, server, and high performance computing (HPC) systems. This paper provides synthetic kernel and natural benchmark results from an HPC system at the NASA Goddard Space Flight Center that illustrate the performance impacts of multi-core (dual- and quad-core) vs. single core processor systems. Analysis of processor design, application source code, and synthetic and natural test results all indicate that multi-core processors can suffer from significant memory subsystem contention compared to similar single-core processors.
Language:
English
Notes:
35th International Computer Measurement Group Conference - CMG'09 Dallas, TX 6-11 Dec. 2009

Title:
Towards Behavioral Reflexion Models
Document ID:
20090038668
Report #:
None
Available Online:
http://hdl.handle.net/2060/20090038668
Sales Agency:
CASI Hardcopy A02 Copyright
Author(s):
Ackermann, Christopher (Fraunhofer USA, Inc.) Lindvall, Mikael (Fraunhofer USA, Inc.) Cleaveland, Rance (Fraunhofer USA, Inc.)
Published:
20090101
Source:
Fraunhofer USA, Inc. (College Park, MD, United States)
Pages:
10
Contract #:
None
Abstract:
Software architecture has become essential in the struggle to manage today s increasingly large and complex systems. Software architecture views are created to capture important system characteristics on an abstract and, thus, comprehensible level. As the system is implemented and later maintained, it often deviates from the original design specification. Such deviations can have implication for the quality of the system, such as reliability, security, and maintainability. Software architecture compliance checking approaches, such as the reflexion model technique, have been proposed to address this issue by comparing the implementation to a model of the systems architecture design. However, architecture compliance checking approaches focus solely on structural characteristics and ignore behavioral conformance. This is especially an issue in Systems-of- Systems. Systems-of-Systems (SoS) are decompositions of large systems, into smaller systems for the sake of flexibility. Deviations of the implementation to its behavioral design often reduce the reliability of the entire SoS. An approach is needed that supports the reasoning about behavioral conformance on architecture level. In order to address this issue, we have developed an approach for comparing the implementation of a SoS to an architecture model of its behavioral design. The approach follows the idea of reflexion models and adopts it to support the compliance checking of behaviors. In this paper, we focus on sequencing properties as they play an important role in many SoS. Sequencing deviations potentially have a severe impact on the SoS correctness and qualities. The desired behavioral specification is defined in UML sequence diagram notation and behaviors are extracted from the SoS implementation. The behaviors are then mapped to the model of the desired behavior and the two are compared. Finally, a reflexion model is constructed that shows the deviations between behavioral design and implementation. This paper discusses the approach and shows how it can be applied to investigate reliability issues in SoS.
Language:
English
Notes:
20th annual International Symposium on Software Reliability Engineering (ISSRE 2009) Bangalore 16-19 Nov. 2009

61-01 COMPUTER SOFTWARE
Nov 22, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Evaluating the Impact of Land Use Change on Submerged Aquatic Vegetation Stressors in Mobile Bay
Document ID:
20090038176
Report #:
M09-0611
Sales Agency:
Other Sources Copyright
Author(s):
Al-Hamdan, Mohammad (NASA Marshall Space Flight Center) Estes, Maurice G., Jr. (NASA Marshall Space Flight Center) Quattrochi, Dale (NASA Marshall Space Flight Center) Thom, Ronald (NASA Marshall Space Flight Center) Woodruff, Dana (NASA Marshall Space Flight Center) Judd, Chaeli (NASA Marshall Space Flight Center) Ellis, Jean (NASA Marshall Space Flight Center) Watson, Brian (NASA Marshall Space Flight Center) Rodriquez, Hugo (NASA Marshall Space Flight Center) Johnson, Hoyt (NASA Marshall Space Flight Center)
Published:
20090909
Source:
NASA Marshall Space Flight Center (Huntsville, AL, United States)
Pages:
1
Contract #:
None
Abstract:
Alabama coastal systems have been subjected to increasing pressure from a variety of activities including urban and rural development, shoreline modifications, industrial activities, and dredging of shipping and navigation channels. The impacts on coastal ecosystems are often observed through the use of indicator species. One such indicator species for aquatic ecosystem health is submerged aquatic vegetation (SAV). Watershed and hydrodynamic modeling has been performed to evaluate the impact of land use change in Mobile and Baldwin counties on SAV stressors and controlling factors (temperature, salinity, and sediment) in Mobile Bay. Watershed modeling using the Loading Simulation Package in C++ (LSPC) was performed for all watersheds contiguous to Mobile Bay for land use scenarios in 1948, 1992, 2001, and 2030. Landsat-derived National Land Cover Data (NLCD) were used in the 1992 and 2001 simulations after having been reclassified to a common classification scheme. The Prescott Spatial Growth Model was used to project the 2030 land use scenario based on current trends. The LSPC model simulations provided output on changes in flow, temperature, and sediment for 22 discharge points into the Bay. Theses results were inputted in the Environmental Fluid Dynamics Computer Code (EFDC) hydrodynamic model to generate data on changes in temperature, salinity, and sediment on a grid with four vertical profiles throughout Mobile Bay. The changes in the aquatic ecosystem were used to perform an ecological analysis to evaluate the impact on SAV habitat suitability. This is the key product benefiting the Mobile Bay coastal environmental managers that integrates the influences of temperature, salinity, and sediment due to land use driven flow changes with the restoration potential of SAVs.
Language:
English
Notes:
23rd Alabama Water Resources Conference and AWRA Symposium Orange Beach, AL 9-11 Sep. 2009

Title:
Characterising Sunspot Complexity for Space Weather Applications
Document ID:
20090038398
Report #:
AD-A506641
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Gallagher, Peter T
Published:
20080101
Source:
Imagine Technologies Ltd. (Dublin, Ireland)
Pages:
10
Contract #:
FA8655-06-M-4006
Abstract:
This report results from a contract tasking Imagine Technologies Ltd as follows: Months 1-3. Collect and Process GONG and SOHO/MDI magnetograms: Ten years of solar magnetic field measurements from the Michelson Doppler Imaginer (MDI) onboard the ESA/NASA Solar and Heliospheric Observatory (SOHO) will be collected, together with complimentary magnetograms from the global network of ground-based magnetographs, GONG. Using sunspot positions from daily USAF/NOAA Solar Region Summaries, a magnetogram will be extracted for each region over this ten-year period. This will result in a sample size of close to 10,000 sunspots groups. Sunspot magnetograms will then be corrected for line-of-site effects, by applying a cosine correction to the data. Sunspots at high latitudes or at longitudes of greater that approximately +/-60 degrees will be disregarded from our sample, due to the uncertainty associated with reconstructing their true magnetic fields. Each of these steps will be carried out using existing software from the Solar SoftWare library in addition to some additional purpose written routines.
Language:
English

Title:
Preliminary Stages for Integrated Text and Line Drawing Information Extraction
Document ID:
20090038675
Report #:
AD-A506630, AFRL-RI-RS-TM-2009-2
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Stanulevich, Jessica
Published:
20090901
Source:
Air Force Research Lab. (Rome, NY United States)
Pages:
27
Contract #:
None
Abstract:
This paper presents research by a college-bound student during her summer job. The project involved experimenting with a piece of commercial image processing software, analyzing line drawings with associated text towards the ability to recognize the semantic content of editorial cartoons. The goal of this summer project was to initiate the research to enable the recognition of full, frontal faces in simple line drawings.
Language:
English

Title:
Technology Infusion of CodeSonar into the Space Network Ground Segment
Document ID:
20090038682
Report #:
None
Available Online:
http://hdl.handle.net/2060/20090038682
Sales Agency:
CASI Hardcopy A03 No Copyright
Author(s):
Benson, Markland J. (NASA Goddard Space Flight Center)
Published:
20090922
Source:
NASA Goddard Space Flight Center (Greenbelt, MD, United States)
Pages:
31
Contract #:
None
Abstract:
This slide presentation reviews the applicability of CodeSonar to the Space Network software. CodeSonar is a commercial off the shelf system that analyzes programs written in C, C++ or Ada for defects in the code. Software engineers use CodeSonar results as an input to the existing source code inspection process. The study is focused on large scale software developed using formal processes. The systems studied are mission critical in nature but some use commodity computer systems.
Language:
English
Notes:
Software Assurance Symposium (SAS) '09/NASA Software Assurance Research Program (SARP) Fairmont, WV 22-23 Sep. 2009

Title:
Connecting Research and Practice: An Experience Report on Research Infusion with SAVE
Document ID:
20090038684
Report #:
None
Available Online:
http://hdl.handle.net/2060/20090038684
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Lindvall, Mikael (Maryland Univ.) Stratton, William C. (Johns Hopkins Univ.) Sibol, Deane E. (Johns Hopkins Univ.) Ackermann, Christopher (Maryland Univ.) Reid, W. Mark (Johns Hopkins Univ.) Ganesan, Dharmalingam (Maryland Univ.) McComas, David (NASA Goddard Space Flight Center) Bartholomew, Maureen (NASA Goddard Space Flight Center) Godfrey, Sally (NASA Goddard Space Flight Center)
Published:
20090101
Source:
Maryland Univ. (College Park, MD, United States)
Pages:
36
Contract #:
None
Abstract:
NASA systems need to be highly dependable to avoid catastrophic mission failures. This calls for rigorous engineering processes including meticulous validation and verification. However, NASA systems are often highly distributed and overwhelmingly complex, making the software portion of these systems challenging to understand, maintain, change, reuse, and test. NASA's systems are long-lived and the software maintenance process typically constitutes 60-80% of the total cost of the entire lifecycle. Thus, in addition to the technical challenges of ensuring high life-time quality of NASA's systems, the post-development phase also presents a significant financial burden. Some of NASA's software-related challenges could potentially be addressed by some of the many powerful technologies that are being developed in software research laboratories. Many of these research technologies seek to facilitate maintenance and evolution by for example architecting, designing and modeling for quality, flexibility, and reuse. Other technologies attempt to detect and remove defects and other quality issues by various forms of automated defect detection, architecture analysis, and various forms of sophisticated simulation and testing. However promising, most such research technologies nevertheless do not make the transition from the research lab to the software lab. One reason the transition from research to practice seldom occurs is that research infusion and technology transfer is difficult. For example, factors related to the technology are sometimes overshadowed by other types of factors such as reluctance to change and therefore prohibits the technology from sticking. Successful infusion might also take very long time. One famous study showed that the discrepancy between the conception of the idea and its practical use was 18 years plus or minus three. Nevertheless, infusing new technology is possible. We have found that it takes special circumstances for such research infusion to succeed: 1) there must be evidence that the technology works in the practitioner's particular domain, 2) there must be a potential for great improvements and enhanced competitive edge for the practitioner, 3) the practitioner has to have strong individual curiosity and continuous interest in trying out new technologies, 4) the practitioner has to have support on multiple levels (i.e. from the researchers, from management, from sponsors etc), and 5) to remain infused, the new technology has to be integrated into the practitioner's processes so that it becomes a natural part of the daily work. NASA IV&V's Research Infusion initiative sponsored by NASA's Office of Safety & Mission Assurance (OSMA) through the Software Assurance Research Program (SARP), strives to overcome some of the problems related to research infusion.
Language:
English
Notes:
To be submitted to Innovations in Systems and Software Engineering a NASA Journal

Title:
Fully Employing Software Inspections Data
Document ID:
20090038685
Report #:
None
Available Online:
http://hdl.handle.net/2060/20090038685
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Shull, Forrest (Maryland Univ.) Feldmann, Raimund L. (Maryland Univ.) Seaman, Carolyn (Maryland Univ.) Regardie, Myrna (Maryland Univ.) Godfrey, Sally (NASA Goddard Space Flight Center)
Published:
20090101
Source:
Maryland Univ. (College Park, MD, United States)
Pages:
19
Contract #:
None
Abstract:
Software inspections provide a proven approach to quality assurance for software products of all kinds, including requirements, design, code, test plans, among others. Common to all inspections is the aim of finding and fixing defects as early as possible, and thereby providing cost savings by minimizing the amount of rework necessary later in the lifecycle. Measurement data, such as the number and type of found defects and the effort spent by the inspection team, provide not only direct feedback about the software product to the project team but are also valuable for process improvement activities. In this paper, we discuss NASA's use of software inspections and the rich set of data that has resulted. In particular, we present results from analysis of inspection data that illustrate the benefits of fully utilizing that data for process improvement at several levels. Examining such data across multiple inspections or projects allows team members to monitor and trigger cross project improvements. Such improvements may focus on the software development processes of the whole organization as well as improvements to the applied inspection process itself.
Language:
English
Notes:
To be submitted to Innovations in Systems and Software Engineering a NASA Journal

Title:
LAURA Users Manual: 5.2-43231
Document ID:
20090038726
Report #:
NASA/TM-2009-215944, LF99-9703, L-19783
Available Online:
http://hdl.handle.net/2060/20090038726
Sales Agency:
CASI Hardcopy A05 Copyright
Author(s):
Mazaheri, Alireza (Analytical Mechanics Associates, Inc.) Gnoffo, Peter A. (NASA Langley Research Center) Johnston, Christopher O. (NASA Langley Research Center) Kleb, Bil (NASA Langley Research Center)
Published:
20091101
Source:
NASA Langley Research Center (Hampton, VA, United States)
Pages:
86
Contract #:
None
Abstract:
This users manual provides in-depth information concerning installation and execution of LAURA, version 5. LAURA is a structured, multi-block, computational aerothermodynamic simulation code. Version 5 represents a major refactoring of the original Fortran 77 LAURA code toward a modular structure afforded by Fortran 95. The refactoring improved usability and maintainability by eliminating the requirement for problem-dependent re-compilations, providing more intuitive distribution of functionality, and simplifying interfaces required for multiphysics coupling. As a result, LAURA now shares gas-physics modules, MPI modules, and other low-level modules with the FUN3D unstructured-grid code. In addition to internal refactoring, several new features and capabilities have been added, e.g., a GNU-standard installation process, parallel load balancing, automatic trajectory point sequencing, free-energy minimization, and coupled ablation and flowfield radiation.
Language:
English

Title:
Progress Report for FACETS (Framwork Application for Core-Edge Transport Simulations)
Document ID:
20090038806
Report #:
DE2009-952094, LLNL-TR-412434
Sales Agency:
Department of Energy Information Bridge No Copyright
Author(s):
Epperly, T. G. W.
Published:
20090422
Source:
Lawrence Livermore National Lab. (Livermore, CA United States)
Pages:
5
Contract #:
None
Abstract:
This role of this computer science SAP is to facilitate FACETS design and development by contributing CCA component technology and new application-specific technology. From a software perspective, the FACETS project is a very complex project. It is a combination of legacy software written in Fortran, Python, and C++ by various coding groups along with new software modules being written from scratch. The FACETS team is spread among 11 organizations and is geographically distributed from coast to coast. The fusion physics modules to be incorporated vary in terms of the model dimensions, typical time scale, and type of interactions with other components. Because FACETS is a complex project, it requires a component-based framework to facilitate the definition and composition of scientific applications from a suite of available fusion physics components. Component architectures have proven themselves in the business world and more recently in the scientific computing world. The CS SAP contributes fundamental tools like Babel to the FACETS framework and helps develop application-specific interfaces appropriate for the fusion physics modules.
Language:
English
Notes:
Sponsored by Department of Energy, Washington, DC.

61-02 CAD/CAM
Nov 22, 2009 -- Additions to the NASA scientific and technical information knowledge base

No records are available for this topic on this date.

63-01 CYBERNETICS AND BIONICS
Nov 22, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Advanced Avionics and Processor Systems for Space and Lunar Exploration
Document ID:
20090037678
Report #:
M09-0738, M09-0761
Available Online:
http://hdl.handle.net/2060/20090037678
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Keys, Andrew S. (NASA Marshall Space Flight Center) Adams, James H. (NASA Marshall Space Flight Center) Ray, Robert E. (Jacobs Engineering Group, Inc.) Johnson, Michael A. (NASA Goddard Space Flight Center) Cressler, John D. (Georgia Inst. of Tech.)
Published:
20090914
Source:
NASA Marshall Space Flight Center (Huntsville, AL, United States)
Pages:
40
Contract #:
None
Abstract:
NASA's newly named Advanced Avionics and Processor Systems (AAPS) project, formerly known as the Radiation Hardened Electronics for Space Environments (RHESE) project, endeavors to mature and develop the avionic and processor technologies required to fulfill NASA's goals for future space and lunar exploration. Over the past year, multiple advancements have been made within each of the individual AAPS technology development tasks that will facilitate the success of the Constellation program elements. This paper provides a brief review of the project's recent technology advancements, discusses their application to Constellation projects, and addresses the project's plans for the coming year.
Language:
English
Notes:
AIAA SPACE 2009 Conference and Exposition Pasadena, CA 14-17 Sep. 2009

63-02 ARTIFICIAL INTELLIGENCE
Nov 22, 2009 -- Additions to the NASA scientific and technical information knowledge base

No records are available for this topic on this date.

64-01 NUMERICAL ANALYSIS
Nov 22, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Nonlinear Localized Dissipative Structures for Long-Time Solution of Wave Equation
Document ID:
20090038223
Report #:
AD-A506308
Available Online:
http://hdl.handle.net/100.2/ADA506308
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Steinhoff, John
Published:
20090701
Source:
Tennessee Univ. Space Inst. (Tullahoma, TN United States)
Pages:
43
Contract #:
FA9550-05-1-0354
Abstract:
A new numerical method, Wave Confinement (WC), is developed to efficiently solve the linear wave equation. This is similar to the originally developed Vorticity Confinement method for fluid mechanics problems. It involves modification of the discrete wave equation by adding an extra nonlinear term that can accurately propagate the pulses for long distances without numerical dispersion/diffusion. These pulses are propagated as stable codimension-one surfaces and do not suffer phase shift or amplitude exchange in spite of nonlinearity. The pulses remain thin unlike conventional higher order numerical schemes, which only converge as N (number of grid cells across the pulse) becomes large. The additional term does not interfere with conservation of the important integral quantities such as total amplitude, centroid. Also, properties like varying index of refraction, diffraction, multiple reflections are included and tested.
Language:
English

Title:
Calculation Of The Nanbu-Trubnikov Kernel: Implications For Numerical Modeling Of Coulomb Collisions. 2009 SIAM Annual Meeting Denver, CO, United States July 6, 2009 through July 10, 2009
Document ID:
20090038293
Report #:
PB2009-115300, LLNL-CONF-414445
Sales Agency:
CASI Hardcopy A03 No Copyright
Author(s):
Dimits, A. M. Cohen, B. I. Wang, C. M. Caflisch, R. Huang, Y.
Published:
20090706
Source:
California Univ., Lawrence Livermore Lab. (Livermore, CA, United States) California Univ. (Los Angeles, CA, United States)
Pages:
39
Contract #:
None
Abstract:
We investigate the accuracy of and assumptions underlying the numerical binary Monte-Carlo collision operator due to Nanbu. The numerical experiments that resulted in Nanbus parameterized collision kernel are approximate realizations of the Coulomb-Lorentz pitch-angle scattering process, for which an analytical solution is available. It is demonstrated empirically that Nanbus collision operator quite accurately recovers the effects of Coulomb-Lorentz pitch angle collisions, or processes that approximate these even for very large values of the collisional time step. An investigation of the analytical solution shows that Nanbus parameterized kernel is highly accurate for small values of the normalized collision time step, but loses some of its accuracy for larger values of the time step. Finally, a practical collision algorithm is proposed that for small-mass-ratio Coulomb collisions improves on the accuracy of Nanbus algorithm.
Language:
English
Notes:
Prepared in cooperation with California Univ., Los Angeles.

Title:
Numerical Optimization of an Annular Field Reserved Configuration Translation Experiment
Document ID:
20090038644
Report #:
AD-A506279, AFRL-RZ-ED-TP-2009-311
Available Online:
http://hdl.handle.net/100.2/ADA506279
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Niemela, Carrie S. (Michigan Technological Univ.) King, Lyon B. (Michigan Technological Univ.)
Published:
20090814
Source:
Air Force Research Lab. (Edwards AFB, CA United States)
Pages:
16
Contract #:
FA9300-06-C-0023
Abstract:
Annular field reversed configuration (AFRC) devices form annular plasma toroids between a pair of concentric cylindrical coils. This plasmoid remains detached from the external magnetic _field so that it can be ejected from the coils, making AFRCs viable pulsed inductive plasma accelerators. Though numerous formation studies on AFRCs are available, no successful translation studies have been published. Michigan Technological University, in conjunction with the Air Force Research Laboratory, is investigating the translation of AFRCs as pulsed inductive plasma accelerators. The first step in this investigation is to develop an annular electromagnetic launcher model to study the basic translation characteristics of the device. The launcher model treats the plasmoid as a rigid conducting slug, accelerated out of the coils by a Lorentz force. It predicts coil and plasmoid currents, plasmoid trajectories, and acceleration efficiencies for various input conditions. The model has been optimized for peak acceleration efficiency using a combination of non-dimensional analysis, genetic algorithms, and gradient-based numerical optimization routines. A description of the model, explanation of the numerical optimization techniques, and preliminary results from the model are presented in this paper.
Language:
English
Notes:
Sponsored in part by DoD contract no. FA9300-06-C-0023 31st International Electric Propulsion Conference Ann Arbor, MI 20-24 Sep. 2009

65-01 PROBABILITY AND STATISTICS
Nov 22, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Unauthorized Aliens Residing in the United States: Estimates Since 1986
Document ID:
20090038351
Report #:
AD-A506449, CRS-RL33874
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Wasem, Ruth E
Published:
20090825
Source:
Library of Congress (Washington, DC United States)
Pages:
17
Contract #:
None
Abstract:
Estimates derived from the March Supplement of the U.S. Census Bureau's Current Population Survey (CPS) indicate that the unauthorized resident alien population (commonly referred to as illegal aliens) rose from 3.2 million in 1986 to 11.9 million in 2008. Jeffrey Passel, a demographer with the Pew Hispanic Research Center, has been involved in making these estimations since he worked at the U.S. Bureau of the Census in the 1980s. The estimated number of unauthorized aliens had dropped to 1.9 million in 1988 following passage of a 1986 law that legalized several million unauthorized aliens. Steven Camarota and Karen Jensenius of the Center for Immigration Studies use the monthly version of the CPS to estimate that the unauthorized resident alien population has fallen to 10.8 million in 2009. The estimates of unauthorized aliens peaked at an estimated 12.4-12.5 million in 2007. About 44% of unauthorized alien residents in 2008 were estimated to have entered the United States in 2000 or later. Similarly, the Department of Homeland Security's Office of Immigration Statistics (OIS) reported an estimated 11.6 million unauthorized alien residents as of January 2008, up from 8.5 million in January 2000. The OIS estimated that 61% of unauthorized alien residents were from Mexico, a percentage comparable to Passel and D'Vera Cohn's calculation of 59% from Mexico. The OIS estimated that the unauthorized resident alien population in the United States increased by 37% over the period 2000 to 2008. Research suggests that various factors have contributed to the ebb and flow of unauthorized resident aliens, and that the increase is often attributed to the push-pull of prosperity-fueled job opportunities in the United States in contrast to limited or nonexistent job opportunities in the sending countries. Also, many foreign nationals who would prefer to come to the United States legally resort to illegal avenues in frustration over visa delays.
Language:
English
Notes:
CRS Report for Congress

Title:
Low Probability of Detection Underwater Acoustic Communications using Direct-Sequence Spread Spectrum
Document ID:
20090038408
Report #:
AD-A506712
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Yang, T C Yang, Wen-Bin
Published:
20081201
Source:
Naval Research Lab. (Washington, DC United States)
Pages:
17
Contract #:
None
Abstract:
Direct-sequence spread spectrum is used for underwater acoustic communications between nodes, at least one of which is moving. At-sea data show that the phase change due to source motion is significant: The differential phase between two adjacent symbols is often larger than the phase difference between symbols. This poses a challenge to phase-detection based receiver algorithms when the source or receiver is moving. A pair of energy detectors that are insensitive to the phase fluctuations is proposed, whose outputs are used to determine the relationship between adjacent symbols. Good performance is achieved for a signal-to-noise ratio SNR as low as -10 dB based on at-sea data. While the method can be applied to signaling using short code sequences, the focus in this paper is on long code sequences for the purpose of achieving a high processing gain at the expense of a low data rate, so that communications can be carried out at a low input SNR to minimize the probability of detection PD by an interceptor. PD is calculated for a typical shallow water environment as a function of range for several source levels assuming a broadband energy detector with a known signal bandwidth.
Language:
English
Notes:
in Journal Acoustic Society of America, v124 n6,p3632-3647, Dec 2008

Title:
Statistical Analysis of a Round-Robin Measurement Survey of Two Candidate Materials for a Seebeck Coefficient Standard Reference Material
Document ID:
20090038442
Report #:
AD-A506836
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Lu, Z Q Lowhorn, Nathan D Wong-Ng, Winnie Zhang, Weiping Otani, Makoto Thomas, Evan E Green, Martin L Tran, Thanh N
Published:
20090201
Source:
Naval Surface Warfare Center (Bethesda, MD United States)
Pages:
20
Contract #:
None
Abstract:
In an effort to develop a Standard Reference Material (SRM(trademark)) for Seebeck coefficient, we have conducted a round-robin measurement survey of two candidate materials-undoped Bi2Te3 and Constantan (55 % Cu and 45 % Ni alloy). Measurements were performed in two rounds by twelve laboratories involved in active thermoelectric research using a number of different commercial and custom-built measurement systems and techniques. In this paper we report the detailed statistical analyses on the interlaboratory measurement results and the statistical methodology for analysis of irregularly sampled measurement curves in the interlaboratory study setting. Based on these results, we have selected Bi2Te3 as the prototype standard material. Once available, this SRM will be useful for future interlaboratory data comparison and instrument calibrations.
Language:
English
Notes:
in Journal of Research of the National Institute of Standards and Technology, v114 n1, p37-55, Jan-Feb 2009

Title:
Plasma Equilibrium in a Magnetic Field with Stochastic Regions
Document ID:
20090038783
Report #:
DE2009-953207, PPPL-4401
Sales Agency:
National Technical Information Service (NTIS) No Copyright
Author(s):
Krommes, J. A. Reiman, A. H.
Published:
20090423
Source:
Princeton Univ. (NJ United States)
Pages:
32
Contract #:
DE-AC02-09CH11466
Abstract:
The nature of plasma equilibrium in a magnetic field with stochastic regions is examined. It is shown that the magnetic differential equation that determines the equilibrium Pfirsch-Schluter currents can be cast in a form similar to various nonlinear equations for a turbulent plasma, allowing application of the mathematical methods of statistical turbulence theory. An analytically tractable model, previously studied in the context of resonance-broadening theory, is applied with particular attention paid to the periodicity constraints required in toroidal configurations. It is shown that even a very weak radial diffusion of the magnetic field lines can have a significant effect on the equilibrium in the neighborhood of the rational surfaces, strongly modifying the near-resonant Pfirsch-Schluter currents. Implications for the numerical calculation of 3D equilibria are discussed.
Language:
English
Notes:
Sponsored by Department of Energy, Washington, DC.