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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Object-Oriented Multi-Disciplinary Design, Analysis, and Optimization Tool

An Object-Oriented Optimization (O3) tool was developed that leverages existing tools and practices, and allows the easy integration and adoption of new state-of-the-art software. At the heart of the O3 tool is the Central Executive Module (CEM), which can integrate disparate software packages in a cross platform network environment so as to quickly perform optimization and design tasks in a cohesive, streamlined manner. This object-oriented framework can integrate the analysis codes for multiple disciplines instead of relying on one code to perform the analysis for all disciplines. The CEM was written in FORTRAN and the script commands for each performance index were submitted through the use of the FORTRAN Call System command. In this CEM, the user chooses an optimization methodology, defines objective and constraint functions from performance indices, and provides starting and side constraints for continuous as well as discrete design variables. The structural analysis modules such as computations of the structural weight, stress, deflection, buckling, and flutter and divergence speeds have been developed and incorporated into the O3 tool to build an object-oriented Multidisciplinary Design, Analysis, and Optimization (MDAO) tool.

Pak, Chan-gi↗
NASA NTRS2002

Preliminary Design and Evaluation of Portable Electronic Flight Progress Strips

There has been growing interest in using electronic alternatives to the paper Flight Progress Strip (FPS) for air traffic control. However, most research has been centered on radar-based control environments, and has not considered the unique operational needs of the airport air traffic control tower. Based on an analysis of the human factors issues for control tower Decision Support Tool (DST) interfaces, a requirement has been identified for an interaction mechanism which replicates the advantages of the paper FPS (e.g., head-up operation, portability) but also enables input and output with DSTs. An approach has been developed which uses a Portable Electronic FPS that has attributes of both a paper strip and an electronic strip. The prototype flight strip system uses Personal Digital Assistants (PDAs) to replace individual paper strips in addition to a central management interface which is displayed on a desktop computer. Each PDA is connected to the management interface via a wireless local area network. The Portable Electronic FPSs replicate the core functionality of paper flight strips and have additional features which provide a heads-up interface to a DST. A departure DST is used as a motivating example. The central management interface is used for aircraft scheduling and sequencing and provides an overview of airport departure operations. This paper will present the design of the Portable Electronic FPS system as well as preliminary evaluation results.

Doble, Nathan A.↗
NASA NTRS2011

Correctness Proof of a Self-Stabilizing Distributed Clock Synchronization Protocol for Arbitrary Digraphs

This report presents a deductive proof of a self-stabilizing distributed clock synchronization protocol. It is focused on the distributed clock synchronization of an arbitrary, non-partitioned digraph ranging from fully connected to 1-connected networks of nodes while allowing for differences in the network elements. This protocol does not rely on assumptions about the initial state of the system, and no central clock or a centrally generated signal, pulse, or message is used. Nodes are anonymous, i.e., they do not have unique identities. There is no theoretical limit on the maximum number of participating nodes. The only constraint on the behavior of the node is that the interactions with other nodes are restricted to defined links and interfaces. We present a deductive proof of the correctness of the protocol as it applies to the networks with unidirectional and bidirectional links. We also confirm the claims of determinism and linear convergence.

Malekpour, Mahyar R.↗
NASA NTRS2014

The EDSN Intersatellite Communications Architecture

The Edison Demonstration of Smallsat Networks (EDSN) is a swarm of eight 1.5U Cubesats developed by the NASA Ames Research Center under the Small Spacecraft Technology Program (SSTP) within NASA Space Technology Mission Directorate (STMD). EDSN, scheduled for launch in late 2014, is designed to explore the use of small spacecraft networks to make synchronized, multipoint scientific measurements, and to organize and pass those data to the ground through their network. Networked swarms of these small spacecraft will open new horizons in astronomy, Earth observations and solar physics. Their range of applications include the formation of synthetic aperture radars for Earth sensing systems, large aperture observatories for next generation telescopes and the collection of spatially distributed measurements of time varying systems, probing the Earth's magnetosphere, Earth-Sun interactions and the Earth's geopotential. The EDSN communications network is maintained and operated by a simple set of predefined rules operating independently on all eight spacecraft without direction from ground based systems. One spacecraft serves as a central node, requesting and collecting data from the other seven spacecraft, organizing the data and passing it to a ground station at regular intervals. The central node is rotated among the spacecraft on a regular basis, providing robustness against the failure of a single spacecraft. This paper describes the communication architecture of the EDSN network and its operation with small spacecraft of limited electrical power, computing power and communication range. Furthermore, the problems of collecting and prioritizing data through a system that has data throughput bottlenecks are addressed. Finally, future network enhancements that can be built on top of the current EDSN hardware are discussed.

Communications↗
NASA NTRS1992

Robustness of a distributed neural network controller for locomotion in a hexapod robot

A distributed neural-network controller for locomotion, based on insect neurobiology, has been used to control a hexapod robot. How robust is this controller? Disabling any single sensor, effector, or central component did not prevent the robot from walking. Furthermore, statically stable gaits could be established using either sensor input or central connections. Thus, a complex interplay between central neural elements and sensor inputs is responsible for the robustness of the controller and its ability to generate a continuous range of gaits. These results suggest that biologically inspired neural-network controllers may be a robust method for robotic control.

Chiel, Hillel J.↗
NASA NTRS2002

A De-Centralized Scheduling and Load Balancing Algorithm for Heterogeneous Grid Environments

In the past two decades, numerous scheduling and load balancing techniques have been proposed for locally distributed multiprocessor systems. However, they all suffer from significant deficiencies when extended to a Grid environment: some use a centralized approach that renders the algorithm unscalable, while others assume the overhead involved in searching for appropriate resources to be negligible. Furthermore, classical scheduling algorithms do not consider a Grid node to be N-resource rich and merely work towards maximizing the utilization of one of the resources. In this paper we propose a new scheduling and load balancing algorithm for a generalized Grid model of N-resource nodes that not only takes into account the node and network heterogeneity, but also considers the overhead involved in coordinating among the nodes. Our algorithm is de-centralized, scalable, and overlaps the node coordination time of the actual processing of ready jobs, thus saving valuable clock cycles needed for making decisions. The proposed algorithm is studied by conducting simulations using the Message Passing Interface (MPI) paradigm.

Arora, Manish↗
NASA NTRS1975

Neural models on temperature regulation for cold-stressed animals

The present review evaluates several assumptions common to a variety of current models for thermoregulation in cold-stressed animals. Three areas covered by the models are discussed: signals to and from the central nervous system (CNS), portions of the CNS involved, and the arrangement of neurons within networks. Assumptions in each of these categories are considered. The evaluation of the models is based on the experimental foundations of the assumptions. Regions of the nervous system concerned here include the hypothalamus, the skin, the spinal cord, the hippocampus, and the septal area of the brain.

Horowitz, J. M.↗
NASA NTRS1988

National Space Science Data Center and World Data Center A for Rockets and Satellites - Ionospheric data holdings and services

The activities and services of the National Space Science data Center (NSSDC) and the World Data Center A for Rockets and Satellites (WDC-A-R and S) are described with special emphasis on ionospheric physics. The present catalog/archive system is explained and future developments are indicated. In addition to the basic data acquisition, archiving, and dissemination functions, ongoing activities include the Central Online Data Directory (CODD), the Coordinated Data Analysis Workshopps (CDAW), the Space Physics Analysis Network (SPAN), advanced data management systems (CD/DIS, NCDS, PLDS), and publication of the NSSDC News, the SPACEWARN Bulletin, and several NSSD reports.

Bilitza, D.↗
NASA NTRS1989

The Aerospace Energy Systems Laboratory: A BITBUS networking application

The NASA Ames-Dryden Flight Research Facility developed a computerized aircraft battery servicing facility called the Aerospace Energy Systems Laboratory (AESL). This system employs distributed processing with communications provided by a 2.4-megabit BITBUS local area network. Customized handlers provide real time status, remote command, and file transfer protocols between a central system running the iRMX-II operating system and ten slave stations running the iRMX-I operating system. The hardware configuration and software components required to implement this BITBUS application are required.

Glover, Richard D.↗
NASA NTRS1993

The Database Query Support Processor (QSP)

The number and diversity of databases available to users continues to increase dramatically. Currently, the trend is towards decentralized, client server architectures that (on the surface) are less expensive to acquire, operate, and maintain than information architectures based on centralized, monolithic mainframes. The database query support processor (QSP) effort evaluates the performance of a network level, heterogeneous database access capability. Air Force Material Command's Rome Laboratory has developed an approach, based on ANSI standard X3.138 - 1988, 'The Information Resource Dictionary System (IRDS)' to seamless access to heterogeneous databases based on extensions to data dictionary technology. To successfully query a decentralized information system, users must know what data are available from which source, or have the knowledge and system privileges necessary to find out this information. Privacy and security considerations prohibit free and open access to every information system in every network. Even in completely open systems, time required to locate relevant data (in systems of any appreciable size) would be better spent analyzing the data, assuming the original question was not forgotten. Extensions to data dictionary technology have the potential to more fully automate the search and retrieval for relevant data in a decentralized environment. Substantial amounts of time and money could be saved by not having to teach users what data resides in which systems and how to access each of those systems. Information describing data and how to get it could be removed from the application and placed in a dedicated repository where it belongs. The result simplified applications that are less brittle and less expensive to build and maintain. Software technology providing the required functionality is off the shelf. The key difficulty is in defining the metadata required to support the process. The database query support processor effort will provide quantitative data on the amount of effort required to implement an extended data dictionary at the network level, add new systems, adapt to changing user needs, and provide sound estimates on operations and maintenance costs and savings.

Source record↗
NASA NTRS2011

Implementing Strategic Planning Capabilities Within the Mars Relay Operations Service

Since the Mars Exploration Rovers (MER), Spirit and Opportunity, began their travels across the Martian surface in January of 2004, orbiting spacecraft such as the Mars 2001 Odyssey orbiter have relayed the majority of their collected scientific and operational data to and from Earth. From the beginning of those missions, it was evident that using orbiters to relay data to and from the surface of Mars was a vastly more efficient communications strategy in terms of power consumption and bandwidth compared to direct-to-Earth means. However, the coordination between the various spacecraft, which are largely managed independently and on differing commanding timelines, has always proven to be a challenge. Until recently, the ground operators of all these spacecraft have coordinated the movement of data through this network using a collection of ad hoc human interfaces and various, independent software tools. The Mars Relay Operations Service (MaROS) has been developed to manage the evolving needs of the Mars relay network, and specifically to standardize and integrate the relay planning and coordination data into a centralized infrastructure. This paper explores the journey of developing the MaROS system, from inception to delivery and acceptance by the Mars mission users.

tactical planning↗
NASA NTRS1996

Understanding Customer Dissatisfaction with Underutilized Distributed File Servers

An important trend in the design of storage subsystems is a move toward direct network attachment. Network-attached storage offers the opportunity to off-load distributed file system functionality from dedicated file server machines and execute many requests directly at the storage devices. For this strategy to lead to better performance, as perceived by users, the response time of distributed operations must improve. In this paper we analyze measurements of an Andrew file system (AFS) server that we recently upgraded in an effort to improve client performance in our laboratory. While the original server's overall utilization was only about 3%, we show how burst loads were sufficiently intense to lead to period of poor response time significant enough to trigger customer dissatisfaction. In particular, we show how, after adjusting for network load and traffic to non-project servers, 50% of the variation in client response time was explained by variation in server central processing unit (CPU) use. That is, clients saw long response times in large part because the server was often over-utilized when it was used at all. Using these measures, we see that off-loading file server work in a network-attached storage architecture has to potential to benefit user response time. Computational power in such a system scales directly with storage capacity, so the slowdown during burst period should be reduced.

Riedel, Erik↗
NASA NTRS2002

Neural substrates linking balance control and anxiety

This communication provides an update of our understanding of the neurological bases for the close association between balance control and anxiety. New data suggest that a vestibulo-recipient region of the parabrachial nucleus (PBN) contains cells that respond to body rotation and position relative to gravity. The PBN, with its reciprocal relationships with the extended central amygdaloid nucleus, infralimbic cortex, and hypothalamus, appears to be an important node in a primary network that processes convergent vestibular, somatic, and visceral information processing to mediate avoidance conditioning, anxiety, and conditioned fear responses. Noradrenergic and serotonergic projections to the vestibular nuclei also have parallel connections with anxiety pathways. The coeruleo-vestibular pathway originates in caudal locus coeruleus (LC) and provides regionally specialized noradrenergic input to the vestibular nuclei, which likely mediate effects of alerting and vigilance on the sensitivity of vestibulo-motor circuits. Both serotonergic and nonserotonergic pathways from the dorsal raphe nucleus and the nucleus raphe obscurus also project differentially to the vestibular nuclei, and 5-HT(2A) receptors are expressed in amygdaloid and cortical targets of the PBN. It is proposed that the dorsal raphe nucleus pathway contributes to both (a) a tradeoff between motor and sensory (information gathering) aspects of responses to self-motion and (b) a calibration of the sensitivity of affective responses to aversive aspects of motion. This updated neurologic model continues to be a synthetic schema for investigating the neurological and neurochemical bases for comorbidity of balance disorders and anxiety disorders.

Review↗
NASA NTRS2012

NASA Integrated Network COOP

Natural disasters, terrorist attacks, civil unrest, and other events have the potential of disrupting mission-essential operations in any space communications network. NASA's Space Communications and Navigation office (SCaN) is in the process of studying options for integrating the three existing NASA network elements, the Deep Space Network, the Near Earth Network, and the Space Network, into a single integrated network with common services and interfaces. The need to maintain Continuity of Operations (COOP) after a disastrous event has a direct impact on the future network design and operations concepts. The SCaN Integrated Network will provide support to a variety of user missions. The missions have diverse requirements and include anything from earth based platforms to planetary missions and rovers. It is presumed that an integrated network, with common interfaces and processes, provides an inherent advantage to COOP in that multiple elements and networks can provide cross-support in a seamless manner. The results of trade studies support this assumption but also show that centralization as a means of achieving integration can result in single points of failure that must be mitigated. The cost to provide this mitigation can be substantial. In support of this effort, the team evaluated the current approaches to COOP, developed multiple potential approaches to COOP in a future integrated network, evaluated the interdependencies of the various approaches to the various network control and operations options, and did a best value assessment of the options. The paper will describe the trade space, the study methods, and results of the study.

Continuity of Operations (COOP)↗
NASA NTRS1976

Plasma diagnostic techniques in the ultraviolet - The C III density-sensitive lines in the sun

Spectra and spectroheliograms of the C III transitions at 977 and 1176 A are obtained with the Harvard extreme-ultraviolet spectrometer on Skylab. Analysis of the intensities of these lines, and of their density-sensitive ratio, indicates a wide range of temperature gradients and electron densities in the transition region of various solar features. From values of the observed ratio, we suggest necessary revisions to the excitation rates, and propose a relationship between the ratio and density. The significantly higher ratio found in active regions indicates a density increase of about a factor 2 relative to the network. In the quiet sun, there is no significant difference in density between network and cell interiors, but the uncertainty is as large as a factor 3. The very central 10% of the areas of cell interiors shows a significantly higher density than the mean value for cell interiors.

Dupree, A. K.↗
NASA NTRS1983

TOPEX ground data system

The TOPEX Project is a proposed oceanographic mission to measure the topography of the sea surface for a period of three years. This mission is sponsored by the National Aeronautics and Space Administration and managed by the Jet Propulsion Laboratory. Measurements of topography are used to study ocean currents, tides, bathymetry and the oceanic geoid. Several of the primary goals of this mission are to process and verify the altimetric data, and distribute them within days to the science investigators. This paper describes the TOPEX end-to-end ground data system. In addition to controlling the TOPEX satellite, the ground data system has been designed to minimize the time from data acquisition to science processing and data distribution. A centralized design supports the favorable response time of the system and also allows for operational efficiencies. Networking of real time and non-real time elements of the data system provides for more effective data processing.

Rosell, S. N.↗
NASA NTRS1988

Geodetic measurement of deformation east of the San Andreas Fault in Central California

The shear strain rates in the Diablo Range of California have been calculated, and the slip rate along the Calaveras and Paicines faults in Central California have been estimated, on the basis of triangulation and trilateration data from two geodetic networks located between the western edge of the Great Valley and the San Andreas Fault. The orientation of the principal compressive strain predicted from the azimuth of the major structures in the region is N 25 deg E, leading to an average shear strain value that corresponds to a relative shortening rate of 4.5 + or - 2.4 mm/yr. It is inferred that the measured strain is due to compression across the fold of this area. The hypothesized uniform, fault-normal compression within the Coast Ranges is not supported by these results.

Sauber, Jeanne↗
NASA NTRS1992

Improving regional health care in West Africa using current space systems and technology

This paper discusses the issues involved with establishing an integrated satellite health network in West Africa based on currently available technology. The system proposed makes use of a central national facility capable of transmitting and receiving voice/data and video signals from the entire country. Regional, field and local facilities provides timely epidemiologic information, sharing of medical expertise through telemedical consultations, enhances optimized resource distribution and builds a framework for telecommunications for the entire country.

Jemison, Mae C.↗