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At least 775 records · Page 43

MACH 3: Past and future approaches to intelligent tutoring

In 1986, the U.S. Army Research Institute created an intelligent tutoring system as a proof-of-concept for artificial intelligence applications in Army training. The Maintenance Aid Computer HAWK Intelligent Institutional Instructor (MACH 3) taught student mechanics to maintain and troubleshoot the AN/MPQ-57 High Power Illuminator Radar (HPIR) of the HAWK Air Defense Missile System. In 1989, TRADOC Analysis Command compared the effectiveness of MACH 3 to traditional paper-based troubleshooting drills. For the study, all students received lecture and hands-on training as usual. However, during troubleshooting drills, students traced faults using either MACH 3 or the traditional paper-based method. Class records showed that the MACH 3 group completed significantly more troubleshooting tasks and progressed through tasks of greater difficulty than the paper-based group. Upon completion of training, students took written, practical, and oral essay tests. Mean test scores showed that students performed similarly regardless of the drill method used. However, significantly different standard deviations showed that the MACH 3 group performed more consistently than the paper-based group. Furthermore, significantly different time measures showed that the MACH 3 group reached faster troubleshooting solutions on the actual radar transmitter than the paper-based group. We will present the study results and discuss how updating the design of the MACH 3 can include desktop computing in a virtual environment.

Acchione-Noel, Sylvia↗

Apparatus Would Position Bright Spot On Projection Screen

Proposed apparatus aims beam of visible light at wavelength lambda(2) to create bright spot at desired position in image on projection screen. Intended to replace handheld laser and flashlight pointers lecturers sometimes use to indicate features in projected images. Beam of light cannot be inadvertently aimed toward audience.

Rayman, Marc D.↗

Sea WiFS Technical Report Series: The fourth SeaWIFS Intercalibration Round-Robin Experiment (SIRREX-4), May 1995

This report documents the fourth Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Intercalibration Round-Robin Experiment (SIRREX-4), which was held at the National Institute of Standards and Technology (NIST) on 3-10 May 1995. The agenda for SIRREX-4 was established by a consensus reached at the conclusion of SIRREX-3: there should be an emphasis on training and work to foster and encourage uniform use of accepted protocols for calibrating radiometric instruments in the laboratory. The goal was to host the activity in a setting where proper techniques could be discussed and demonstrated. It seemed appealing to split the day between morning lectures and afternoon laboratory exercises or practicals. The former gave the user community a chance to present what was important to them and discuss it with acknowledged experts in radiometry, while the latter presented a unique opportunity for training and evaluation in the presence of these same experts. The five laboratory sessions were concerned with (1) determining the responsivity of a spectroradiometer and the spectral radiance of an unknown integrating sphere source, (2) demonstrating spectral field calibration procedures for an integrating sphere using three different instruments, (3) measuring spectral radiance using the plaque method, (4) setting up and aligning lamp calibration transfer standards using the NIST specifications for irradiance measurements, and (5) characterizing radiometric instruments. In addition to documenting some supplemental studies performed outside the laboratory sessions, this report includes an evaluation of the hardware that has been used during the SIRREX activities plus a critical evaluation of SIRREX objectives.

Johnson, B. Carol↗

Investigation of source location determination from Magsat magnetic anomalies: The Euler method approach

The applicability of the Euler method of source location determination was investigated on several model situations pertinent to satellite-data scale situations as well as Magsat data of Europe. Our investigations enabled us to understand the end-member cases for which the Euler method will work with the present satellite magnetic data and also the cases for which the assumptions implicit in the Euler method will not be met by the present satellite magnetic data. These results have been presented in one invited lecture at the Indo-US workshop on Geomagnetism in Studies of the Earth's Interior in August 1994 in Pune, India, and at one presentation at the 21st General Assembly of the IUGG in July 1995 in Boulder, CO. A new method, called Anomaly Attenuation Rate (AAR) Method (based on the Euler method), was developed during this study. This method is scale-independent and is appropriate to locate centroids of semi-compact three dimensional sources of gravity and magnetic anomalies. The method was presented during 1996 Spring AGU meeting and a manuscript describing this method is being prepared for its submission to a high-ranking journal. The grant has resulted in 3 papers and presentations at national and international meetings and one manuscript of a paper (to be submitted shortly to a reputable journal).

Ravat, Dhananjay↗

An Exercise in Ion Beam Analysis

Scattering phenomena are taught in introductory physics classes, and concepts such as conservation of energy and momentum are used at all levels of physics. However, applications of scattering are often not included as part of an education. Rutherford scattering, a topic of any modern physics course, is now used as a tool for materials science applications. In the absence of lab equipment for students to perform such experiments, an exercise in the analysis of scattering data may accent the useful concepts given in lectures. The objective of this exercise is to analyze data from Rutherford backscattering experiments in order to determine elemental composition.

Kern, Kristen T.↗

Howard University Energy Expert Systems Institute Summer Program (EESI)

Howard University, under the auspices of the Center for Energy Systems and Controls runs the Energy Expert Systems Institute (EESI) summer outreach program for high school/pre-college minority students. The main objectives are to introduce precollege minority students to research in the power industry using modern state-of-the-art technology such as Expert Systems, Fuzzy Logic and Artificial Neural Networks; to involve minority students in space power management, systems and failure diagnosis; to generate interest in career options in electrical engineering; and to experience problem-solving in a teamwork environment consisting of faculty, senior research associates and graduate students. For five weeks the students are exposed not only to the exciting experience of college life, but also to the inspiring field of engineering, especially electrical engineering. The program consists of lectures in the fundamentals of engineering, mathematics, communication skills and computer skills. The projects are divided into mini and major. Topics for the 1995 mini projects were Expert Systems for the Electric Bus and Breast Cancer Detection. Topics on the major projects include Hybrid Electric Vehicle, Solar Dynamics and Distribution Automation. On the final day, designated as 'EESI Day' the students did oral presentations of their projects and prizes were awarded to the best group. The program began in the summer of 1993. The reaction from the students has been very positive. The program also arranges field trips to special places of interest such as the NASA Goddard Space Center.

Momoh, James A.↗

Technical Reports: Langley Aerospace Research Summer Scholars

The Langley Aerospace Research Summer Scholars (LARSS) Program was established by Dr. Samuel E. Massenberg in 1986. The program has increased from 20 participants in 1986 to 114 participants in 1995. The program is LaRC-unique and is administered by Hampton University. The program was established for the benefit of undergraduate juniors and seniors and first-year graduate students who are pursuing degrees in aeronautical engineering, mechanical engineering, electrical engineering, material science, computer science, atmospheric science, astrophysics, physics, and chemistry. Two primary elements of the LARSS Program are: (1) a research project to be completed by each participant under the supervision of a researcher who will assume the role of a mentor for the summer, and (2) technical lectures by prominent engineers and scientists. Additional elements of this program include tours of LARC wind tunnels, computational facilities, and laboratories. Library and computer facilities will be available for use by the participants.

Schwan, Rafaela↗

Langley Aerospace Research Summer Scholars

The Langley Aerospace Research Summer Scholars (LARSS) Program was established by Dr. Samuel E. Massenberg in 1986. The program has increased from 20 participants in 1986 to 114 participants in 1995. The program is LaRC-unique and is administered by Hampton University. The program was established for the benefit of undergraduate juniors and seniors and first-year graduate students who are pursuing degrees in aeronautical engineering, mechanical engineering, electrical engineering, material science, computer science, atmospheric science, astrophysics, physics, and chemistry. Two primary elements of the LARSS Program are: (1) a research project to be completed by each participant under the supervision of a researcher who will assume the role of a mentor for the summer, and (2) technical lectures by prominent engineers and scientists. Additional elements of this program include tours of LARC wind tunnels, computational facilities, and laboratories. Library and computer facilities will be available for use by the participants.

Schwan, Rafaela↗

Current Perspectives in High Energy Astrophysics

High energy astrophysics is a space-age discipline that has taken a quantum leap forward in the 1990s. The observables are photons and particles that are unable to penetrate the atmosphere and can only be observed from space or very high altitude balloons. The lectures presented as chapters of this book are based on the results from the Compton Gamma-Ray Observatory (CGRO) and Advanced Satellite for Cosmology and Astrophysics (ASCA) missions to which the Laboratory for High Energy Astrophysics at NASA's Goddard Space Flight Center made significant hardware contributions. These missions study emissions from very hot plasmas, nuclear processes, and high energy particle interactions in space. Results to be discussed include gamma-ray beaming from active galactic nuclei (AGN), gamma-ray emission from pulsars, radioactive elements in the interstellar medium, X-ray emission from clusters of galaxies, and the progress being made to unravel the gamma-ray burst mystery. The recently launched X-ray Timing Explorer (XTE) and prospects for upcoming Astro-E and Advanced X-ray Astronomy Satellite (AXAF) missions are also discussed.

Ormes, Jonathan F.↗

The Merging of Fatigue and Fracture Mechanics Concepts: A Historical Perspective

The seventh Jerry L. Swedlow Memorial Lecture presents a review of some of the technical developments, that have occurred during the past 40 years, which have led to the merger of fatigue and fracture mechanics concepts. This review is made from the viewpoint of 'crack propagation.' As methods to observe the 'fatigue' process have improved, the formation of fatigue micro-cracks have been observed earlier in life and the measured crack sizes have become smaller. These observations suggest that fatigue damage can now be characterized by 'crack size.' In parallel, the crack-growth analysis methods, using stress-intensity factors, have also improved. But the effects of material inhomogeneities, crack-fracture mechanisms, and nonlinear behavior must now be included in these analyses. The discovery of crack-closure mechanisms, such as plasticity, roughness, and oxide/corrosion/fretting product debris, and the use of the effective stress-intensity factor range, has provided an engineering tool to predict small- and large-crack-growth rate behavior under service loading, conditions. These mechanisms have also provided a rationale for developing, new, damage-tolerant materials. This review suggests that small-crack growth behavior should be viewed as typical behavior, whereas large-crack threshold behavior should be viewed as the anomaly. Small-crack theory has unified 'fatigue' and 'fracture mechanics' concepts; and has bridged the cap between safe-life and durability/damage-tolerance design concepts.

Newman, James C., Jr.↗

Current Lewis Turbomachinery Research: Building on our Legacy of Excellence

This Wu Chang-Hua lecture is concerned with the development of analysis and computational capability for turbomachinery flows which is based on detailed flow field physics. A brief review of the work of Professor Wu is presented as well as a summary of the current NASA aeropropulsion programs. Two major areas of research are described in order to determine our predictive capabilities using modern day computational tools evolved from the work of Professor Wu. In one of these areas, namely transonic rotor flow, it is demonstrated that a high level of accuracy is obtainable provided sufficient geometric detail is simulated. In the second case, namely turbine heat transfer, our capability is lacking for rotating blade rows and experimental correlations will provide needed information in the near term. It is believed that continuing progress will allow us to realize the full computational potential and its impact on design time and cost.

Povinelli, Louis A.↗

Remote Sensing of Surficial Process Responses to Extreme Meteorological Events

Changes in the frequency and magnitude of extreme meteorological events are associated with changing environmental means. Such events are important in human affairs, and can also be investigated by orbital remote sensing. During the course of this project, we applied ERS-1, ERS-2, Radarsat, and an airborne sensor (AIRSAR-TOPSAR) to measure flood extents, flood water surface profiles, and flood depths. We established a World Wide Web site (the Dartmouth Flood Observatory) for publishing remote sensing-based maps of contemporary floods worldwide; this is also an online "active archive" that presently constitutes the only global compilation of extreme flood events. We prepared an article for EOS concerning SAR imaging of the Mississippi Valley flood; an article for the International Journal of Remote Sensing on measurement of a river flood wave using ERS-2, began work on an article (since completed and published) on the Flood Observatory for a Geoscience Information Society Proceedings volume, and presented lectures at several Geol. Soc. of America Natl. Meetings, an Assoc. of Amer. Geographers Natl. Meeting, and a Binghamton Geomorphology Symposium (all on SAR remote sensing of the Mississippi Valley flood). We expanded in-house modeling capabilities by installing the latest version of the Army Corps of Engineers RMA two-dimensional hydraulics software and BYU Engineering Graphics Lab's Surface Water Modeling System (finite elements based pre- and post-processors for RMA work) and also added watershed modeling software. We are presently comparing the results of the 2-d flow models with SAR image data. The grant also supported several important upgrades of pc-based remote sensing infrastructure at Dartmouth. During work on this grant, we collaborated with several workers at the U.S. Army Corps of Engineers, Remote Sensing/GIS laboratory (for flood inundation mapping and modeling; particularly of the Illinois River using the AIRSAR/TOPSAR/ERS-2 combined data), with Dr. Karen Prestegaard at the University of Maryland (geomorphological responses to the extreme 1993 flood along the Raccoon drainage in central Iowa), and with Mr Tim Scrom of the Albany National Weather Service River Forecast Center (initial planning for the use of Radarsat and ERS-2 for flood warning). The work thus initiated with this proposal is continuing.

Brakenridge, G. Robert↗

Summer Workshop on the Origins of Stars and Planets

The meeting had broad representation from both the national and international scientific communities. There were 38 oral lectures describing the latest research results pertaining to star and planet formation in young clusters presented at the workshop. In addition there were 65 poster papers describing research in this area also presented at the workshop. Because there was ample space made available by Wellesley College, all posters were up and available throughout the entire duration of the meeting. This insured more than adequate time for all participants to view the posters and interact with their authors. The oral talks were 15 minutes in duration with an additional 15 minutes reserved for questions and discussion. As a result there was considerable discussion and exchange of ideas which insured that the workshop nature of the conference was maintained despite the large attendance. In summary, the workshop was a great success scientifically while at the same time being extremely cost effective. The 1996 workshop exceeded the overall objectives originally set for it.

Lada, Charles J.↗

Fastener Design Course

Richard T. Barrett, Senior Aerospace Engineer of NASA Lewis Research Center presents a comprehensive course on fastener design. A recognized expert in the field of fastener technology Mr. Barrett combines lecture, charts, illustrations with real-world experiences. Topics covered include: materials, plantings and coatings, locking methods threads, joint stiffness, rivets, inserts, nut plates, thread lubricants, design criteria, etc. A workbook accompanies the DVD.

Barrett, Richard T.↗

Studying the Earth's Environment from Space: Computer Laboratory Exercised and Instructor Resources

Studying the Earth's Environment From Space is a two-year project to develop a suite of CD-ROMs containing Earth System Science curriculum modules for introductory undergraduate science classes. Lecture notes, slides, and computer laboratory exercises, including actual satellite data and software, are being developed in close collaboration with Carla Evans of NASA GSFC Earth Sciences Directorate Scientific and Educational Endeavors (SEE) project. Smith and Alfultis are responsible for the Oceanography and Sea Ice Processes Modules. The GSFC SEE project is responsible for Ozone and Land Vegetation Modules. This document constitutes a report on the first year of activities of Smith and Alfultis' project.

Smith, Elizabeth A.↗

Fluid Dynamics Research on Supersonic Aircraft

This report Contains the lecture notes prepared for a Special Course on 'Fluid Dynamics Research on Supersonic Aircraft' organized by the Research and Technology Organization (RTO) Applied Vehicle Technology Panel (AVT). The Course was held at the von Karman Institute for Fluid Dynamics (VKI) Institute, Rhode-Saint-Genese, Belgium 25-29 May 1998. The following topics were covered: History and Economics of Supersonic Transports, Supersonic Aerodynamics, Sonic Boom Theory and Minimization, Multi-Point Design Challenges, Vortex Plume Interactions, Propulsion System Design. Presentations on the major world wide supersonic transport programs were also included. The material assembled in this publication was prepared under the combined sponsorship of the RTO Applied Vehicle Technology Panel, the Consultant and Exchange Program of RTO, and the von Karman Institute (VKI) for Fluid Dynamics.

Source record↗

A Synthesis of Fluid Dynamics and Quantum Chemistry for the Design of Nanoelectronics

In 1959, during a famous lecture entitled "There's Plenty of Room at the Bottom", Richard Feynman focused on the startling technical possibilities that would exist at the limit of miniaturization, that being atomically precise devices with dimensions in the nanometer range. A nanometer is both a convenient unit of length for medium to large sized molecules, and the root of the name of the new interdisciplinary field of "nanotechnology". Essentially, "nanoelectronics" denotes the goal of shrinking electronic devices, such as diodes and transistors, as well as integrated circuits of such devices that can perform logical operations, down to dimensions in the range of 100 nanometers. The thirty-year hiatus in the development of nanotechnology can figuratively be seen as a period of waiting for the bottom-up and atomically precise construction skills of synthetic chemistry to meet the top-down reductionist aspirations of device physics. The sub-nanometer domain of nineteenth-century classical chemistry has steadily grown, and state-of-the-art supramolecular chemistry can achieve atomic precision in non-repeating molecular assemblies of the size desired for nanotechnology. For nanoelectronics in particular, a basic understanding of the electron transport properties of molecules must also be developed. Quantum chemistry provides powerful computational methods that can accurately predict the properties of small to medium sized molecules on a desktop workstation, and those of large molecules if one has access to a supercomputer. Of the many properties of a molecule that quantum chemistry routinely predicts, the ability to carry a current is one that had not even been considered until recently. "Currently", there is a controversy over just how to define this key property. Reminiscent of the situation in high-Tc superconductivity, much of the difficulty arises from the different models that are used to simplify the complex electronic structure of real materials. A model-independent approach has been proposed, that sacrifices the plentiful molecular orbitals and Bloch functions of conventional approaches, for a single three-dimensional observable quantity, the electron momentum density Pi(sub rho). This quantity is simply the probability of any electron having momentum rho, multiplied by the total number of electrons in the system (the position of the electron is uncertain). We have explored the utility of this new approach in providing a fundamental understanding of the electron transport properties of molecules that have provi been nominated as candidates for components in the design of nanoelectronics; phenylene-ethynylene oligomers. Some of the molecular systems that have been studied are sketched below.

MacDougall, Preston J.↗

Kennedy Space Center Coronary Heart Disease Risk Screening Program

The number one cause of death in the U.S. is coronary heart disease (CHD). It is probably a major cause of death and disability in the lives of employees at Kennedy Space Center (KSC) as well. The KSC Biomedical Office used a multifactorial mathematical formula from the Framingham Heart Study to calculate CHD risk probabilities for individuals in a segment of the KSC population that required medical evaluation for job certification. Those assessed to be high-risk probabilities will be targeted for intervention. Every year, several thousand KSC employees require medical evaluations for job related certifications. Most medical information for these evaluations is gathered on-site at one of the KSC or Cape Canaveral Air Station (CCAS) medical clinics. The formula used in the Framingham Heart Study allows calculation of a person's probability of acquiring CHD within 10 years. The formula contains the following variables: Age, Diabetes, Smoking, Left Ventricular Hypertrophy, Blood Pressure (Systolic or Diastolic), Cholesterol, and HDL cholesterol. The formula is also gender specific. It was used to calculate the 10-year probabilities of CHD in KSC employees who required medical evaluations for job certifications during a one-year time frame. This KSC population was profiled and CHD risk reduction interventions could be targeted to those at high risk. Population risk could also be periodically reevaluated to determine the effectiveness of intervention. A 10-year CHD risk probability can be calculated for an individual quite easily while gathering routine medical information. An employee population's CHD risk probability can be profiled graphically revealing high risk segments of the population which can be targeted for risk reduction intervention. The small audience of NASA/contractor physicians, nurses and exercise/fitness professionals at the breakout session received the lecture very well. Approximately one third indicated by a show of hands that they would be interested in implementing a similar program at their NASA Center. Questions were asked pertaining to standardization for age, the validity of using the idealized male values also for the female population, and indications of the screening test's sensitivity and specificity.

Tipton, David A.↗