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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 145 records · Page 8

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NASA NTRS2007

A Demand Access Protocol for Space Applications

This paper describes a demand access protocol for space communications, which is a messaging procedure that facilitates the exchange of resource requests and grants between users and service providers. A minimal set of operational and environmental needs and constraints are assumed since the intent is to keep the protocol flexible and efficient for a wide-range of envisioned NASA robotic and human exploration missions. The protocol described in this document defines the message format and procedures used to ensure proper and correct functioning of a demand access communications system, which must operate under customized resource management policies applied by the users and service providers. This protocol also assumes a minimal set of capabilities from the underlying communications system so that no unique requirements are imposed on the communications sub-systems.

demand access↗

NASA NTRS2004

User Evaluation of the NASA Technical Report Server Recommendation Service

We present the user evaluation of two recommendation server methodologies implemented for the NASA Technical Report Server (NTRS). One methodology for generating recommendations uses log analysis to identify co-retrieval events on full-text documents. For comparison, we used the Vector Space Model (VSM) as the second methodology. We calculated cosine similarities and used the top 10 most similar documents (based on metadata) as 'recommendations'. We then ran an experiment with NASA Langley Research Center (LaRC) staff members to gather their feedback on which method produced the most 'quality' recommendations. We found that in most cases VSM outperformed log analysis of co-retrievals. However, analyzing the data revealed the evaluations may have been structurally biased in favor of the VSM generated recommendations. We explore some possible methods for combining log analysis and VSM generated recommendations and suggest areas of future work.

Nelson, Michael L.↗

NASA NTRS2004

User Evaluation of the NASA Technical Report Server Recommendation Service

We present the user evaluation of two recommendation server methodologies implemented for the NASA Technical Report Server (NTRS). One methodology for generating recommendations uses log analysis to identify co-retrieval events on full-text documents. For comparison, we used the Vector Space Model (VSM) as the second methodology. We calculated cosine similarities and used the top 10 most similar documents (based on metadata) as recommendations . We then ran an experiment with NASA Langley Research Center (LaRC) staff members to gather their feedback on which method produced the most quality recommendations. We found that in most cases VSM outperformed log analysis of co-retrievals. However, analyzing the data revealed the evaluations may have been structurally biased in favor of the VSM generated recommendations. We explore some possible methods for combining log analysis and VSM generated recommendations and suggest areas of future work.

Nelson, Michael L.↗

NASA NTRS1991

Toward a North American Standard for Mobile Data Services

The rapid introduction of digital mobile communications systems is an important part of the emerging digital communications scene. These developments pose both a potential problem and a challenge. On one hand, these separate market driven developments can result in an uncontrolled mixture of analog and digital links which inhibit data modem services across the mobile/Public Switched network (PSTN). On the other hand, the near coincidence of schedules for development of some of these systems, i.e., Digital Cellular, Mobile Satellite, Land Mobile Radio, and ISDN, provides an opportunity to address interoperability problems by defining interfaces, control, and service standards that are compatible among these new services. In this paper we address the problem of providing data services interoperation between mobile terminals and data devices on the PSTN. The expected data services include G3 Fax, asynchronous data, and the government's STU-3 secure voice system, and future data services such as ISDN. We address a common architecture and a limited set of issues that are key to interoperable mobile data services. We believe that common mobile data standards will both improve the quality of data service and simplify the systems for manufacturers, data users, and service providers.

Dean, Richard A.↗

NASA NTRS1992

Toward domain-specific design environments: Some representation ideas from the telecommunications domain

ACME is an experimental environment for investigating new approaches to modeling and analysis of system requirements and designs. ACME is built on and extends object-oriented conceptual modeling techniques and knowledge representation and reasoning (KRR) tools. The most immediate intended use for ACME is to help represent, understand, and communicate system designs during the early stages of system planning and requirements engineering. While our research is ostensibly aimed at software systems in general, we are particularly motivated to make an impact in the telecommunications domain, especially in the area referred to as Intelligent Networks (IN's). IN systems contain the software to provide services to users of a telecommunications network (e.g., call processing services, information services, etc.) as well as the software that provides the internal infrastructure for providing the services (e.g., resource management, billing, etc.). The software includes not only systems developed by the network proprietors but also by a growing group of independent service software providers.

Greenspan, Sol↗

NASA NTRSDate not supplied

Zero Trust and Identity Access Management in Support of Service-Based Urban Air Mobility Applications

Urban Air Mobility environments will contain of a collection of service-based services, which will be typically hosted within cloud infrastructures. The underlying data for these UAM services will need to be secured. One approach to securing these UAM services would be to leverage the Zero Trust framework, that focuses on securing services and associated data, instead of securing the network. An early step in moving towards a Zero Trust framework is to standardize identity access manage support for an ever-widening set of services, where users must explicitly be granted access to each service.

UAM↗

DOE OSTI2026

Analyzing users’ preferences between personal and pooled rideshare services using a mixed logit modeling approach

Ridesharing has become an increasingly popular transportation method over the past decade. Transportation network companies such as Uber and Lyft generally provide two types of rideshare services: personal rideshare, in which users ride alone or with individuals they know, and pooled rideshare, in which users ride with passengers they do not know but share similar routes. Pooled rideshare is capable of reducing energy consumption and traffic in the transportation system in comparison to personal rideshare. Despite the growth in trip volume, ridesharing usage is still low compared to other popular transportation methods in the U.S., particularly traveling in one’s own personal vehicle. Furthermore, pooled rideshare usage is lower than personal rideshare. To understand riders’ preferences, a national survey (N = 2884) was conducted in the U.S. to investigate users’ choice behaviors in rideshare services examining personal versus pooled rideshare. Each survey respondent completed 20 stated-preference scenarios where participants choose between a personal or pooled rideshare option. Based on the responses, a mixed logit model was developed to capture the choice behavior preferences of the participants. The model unveiled the impact of demographic and trip attribute variables on users’ rideshare preferences. The discussion encompassed insights into demographic backgrounds and trip attributes, accompanied by a set of policy recommendations aimed at enhancing future pooled rideshare utilization.

Choice model↗

NASA NTRS1983

Customer premises services market demand assessment 1980 - 2000. Volume 1: Executive summary

Estimates of market demand for domestic civilian telecommunications services for the years 1980 to 2000 are provided. Overall demand, demand or satellite services, demand for satellite delivered Customer Premises Service (CPS), and demand for 30/20 GHz Customer Premises Services are covered. Emphasis is placed on the CPS market and demand is segmented by market, by service, by user class and by geographic region. Prices for competing services are discussed and the distribution of traffic with respect to distance is estimated. A nationwide traffic distribution model for CPS in terms of demand for CPS traffic and earth stations for each of the major SMSAs in the United States are provided.

Gamble, R. B.↗

NASA NTRS1998

US Gateway to SIMBAD Astronomical Database

During the last year the US SIMBAD Gateway Project continued to provide services like user registration to the US users of the SIMBAD database in France. User registration is required by the SIMBAD project in France. Currently, there are almost 3000 US users registered. We also provide user support by answering questions from users and handling requests for lost passwords. We have worked with the CDS SIMBAD project to provide access to the SIMBAD database to US users on an Internet address basis. This will allow most US users to access SIMBAD without having to enter passwords. This new system was installed in August, 1998. The SIMBAD mirror database at SAO is fully operational. We worked with the CDS to adapt it to our computer system. We implemented automatic updating procedures that update the database and password files daily. This mirror database provides much better access to the US astronomical community. We also supported a demonstration of the SIMBAD database at the meeting of the American Astronomical Society in January. We shipped computer equipment to the meeting and provided support for the demonstration activities at the SIMBAD booth. We continued to improve the cross-linking between the SIMBAD project and the Astro- physics Data System. This cross-linking between these systems is very much appreciated by the users of both the SIMBAD database and the ADS Abstract Service. The mirror of the SIMBAD database at SAO makes this connection faster for the US astronomers. The close cooperation between the CDS in Strasbourg and SAO, facilitated by this project, is an important part of the astronomy-wide digital library initiative called Urania. It has proven to be a model in how different data centers can collaborate and enhance the value of their products by linking with other data centers.

Eichhorn, G.↗

NASA NTRS2000

A Distributed Multi-Agent System for Collaborative Information Management and Learning

In this paper, we present DIAMS, a system of distributed, collaborative agents to help users access, manage, share and exchange information. A DIAMS personal agent helps its owner find information most relevant to current needs. It provides tools and utilities for users to manage their information repositories with dynamic organization and virtual views. Flexible hierarchical display is integrated with indexed query search-to support effective information access. Automatic indexing methods are employed to support user queries and communication between agents. Contents of a repository are kept in object-oriented storage to facilitate information sharing. Collaboration between users is aided by easy sharing utilities as well as automated information exchange. Matchmaker agents are designed to establish connections between users with similar interests and expertise. DIAMS agents provide needed services for users to share and learn information from one another on the World Wide Web.

Chen, James R.↗

NASA NTRS1999

US Gateway to SIMBAD Astronomical Database

During the last year the US SIMBAD Gateway Project continued to provide services like user registration to the US users of the SIMBAD database in France. Currently there are over 3400 US users registered. We also provide user support by answering questions from users and handling requests for lost passwords when still necessary. We have implemented in cooperation with the CDS SIMBAD project access to the SIMBAD database for US users on an Internet address basis. This allows most US users to access SIMBAD without having to enter passwords. We have maintained the mirror copy of the SIMBAD database on a server at SAO. This has allowed much faster access for the US users. We also supported a demonstration of the SIMBAD database at the meeting of the American Astronomical Society in January. We shipped computer equipment to the meeting and provided support for the demonstration activities at the SIMBAD booth. We continued to improve the cross-linking between the SIMBAD project and the Astrophysics Data System. This cross-linking between these systems is very much appreciated by the users of both the SIMBAD database and the ADS Abstract Service. The mirror of the SIMBAD database at SAO makes this connection faster for the US astronomers. We exchange information between the ADS and SIMBAD on a daily basis. The close cooperation between the CDS in Strasbourg and SAO, facilitated by this project, is an important part of the astronomy-wide digital library initiative called Urania. It has proven to be a model in how different data centers can collaborate and enhance the value of their products by linking with other data centers.

Eichhorn, G.↗

NASA NTRS2003

US Astronomers Access to SIMBAD in Strasbourg, France

During the last year the US SIMBAD Gateway Project continued to provide services like user registration to the US users of the SIMBAD database in France. Currently there are over 4300 US users registered. We also provided user support by answering questions from users and handling requests for lost passwords when still necessary. Even though almost all users now access SIMBAD without a password, based on hostnames/IP addresses, there are still some users that need individual passwords. We continued to maintain the mirror copy of the SIMBAD database on a server at SAO. This allows much faster access for the US users. During the past year we moved this mirror to a faster server to improve access for the US users. We again supported a demonstration of the SIMBAD database at the meeting of the American Astronomical Society in January. We provided support for the demonstration activities at the SIMBAD booth. We paid part of the fee for the SIMBAD demonstration. We continued to improve the cross-linking between the SIMBAD project and the Astrophysics Data System. This cross-linking between these systems is very much appreciated by the users of both the SIMBAD database and the ADS Abstract Service. The mirror of the SIMBAD database at SAO makes this connection faster for the US astronomers. We exchange information between the ADS and SIMBAD on a daily basis. The close cooperation between the CDS in Strasbourg and SAO, facilitated by this project, is an important part of the astronomy-wide digital library initiative. It has proven to be a model in how different data centers can collaborate and enhance the value of their products by linking with other data centers. We continue this collaboration in order to provide better services to both the US and European astronomical community. This collaboration is even more important in light of the developments for the Virtual Observatory projects in the different countries.

Eichhorn, G.↗

NASA NTRS2004

US Astronomers Access to SIMBAD in Strasbourg

During the last year the US SIMBAD Gateway Project continued to provide services like user registration to the US users of the SIMBAD database in France. Currently there are over 4500 US users registered. We also provided user support by answering questions from users and handling requests for lost passwords when still necessary. Even though almost all users now access SIMBAD without a password, based on hostnames/IP addresses, there are still some users that need individual passwords. We continued to maintain the mirror copy of the SIMBAD database on a server at SAO. This allows much faster access for the US users. During the past year we again moved this mirror to a faster server to improve access for the US users. We again supported a demonstration of the SIMBAD database at the meeting of the American Astronomical Society in January. We provided support for the demonstration activities at the SIMBAD booth. We paid part of the fee for the SIMBAD demonstration. We continued to improve the cross-linking between the SIMBAD project and the Astrophysics Data System. This cross-linking between these systems is very much appreciated by the users of both the SIMBAD database and the ADS Abstract Service. The mirror of the SIMBAD database at SA0 makes this connection faster for the US astronomers. We exchange information between the ADS and SIMBAD on a daily basis. During the last year we also installed a mirror copy of the Vizier system from the CDS, in addition to the SIMBAD mirror.

Oliversen, Ronald↗

NASA NTRS2004

Spaceflight Operations Services Grid Prototype

NASA over the years has developed many types of technologies and conducted various types of science resulting in numerous variations of operations, data and applications. For example, operations range from deep space projects managed by JPL, Saturn and Shuttle operations managed from JSC and KSC, ISS science operations managed from MSFC and numerous low earth orbit satellites managed from GSFC that are varied and intrinsically different but require many of the same types of services to fulfill their missions. Also, large data sets (databases) of Shuttle flight data, solar system projects and earth observing data exist which because of their varied and sometimes outdated technologies are not and have not been fully examined for additional information and knowledge. Many of the applications/systems supporting operational services e.g. voice, video, telemetry and commanding, are outdated and obsolete. The vast amounts of data are located in various formats, at various locations and range over many years. The ability to conduct unified space operations, access disparate data sets and to develop systems and services that can provide operational services does not currently exist in any useful form. In addition, adding new services to existing operations is generally expensive and with the current budget constraints not feasible on any broad level of implementation. To understand these services a discussion of each one follows. The Spaceflight User-based Services are those services required to conduct space flight operations. Grid Services are those Grid services that will be used to overcome, through middleware software, some or all the problems that currently exists. In addition, Network Services will be discussed briefly. Network Services are crucial to any type of remedy and are evolving adequately to support any technology currently in development.

Bradford, Robert N.↗

NASA NTRS1983

Organizational structure and operation of defense/aerospace information centers in the United States of America

U.S. Government aerospace and defense information centers are addressed. DTIC and NASA are described in terms of their history, operational authority, information services provided, user community, sources of information collected, efforts under way to improve services, and external agreements regarding the exchange of documents and/or data bases. Contents show how DTIC and NASA provide aerospace/defense information services in support of U.S. research and development efforts. In a general introduction, the importance of scientific and technical information and the need for information centers to acquire, handle, and disseminate it are stressed.

Sauter, H. E.↗

NASA NTRSDate not supplied

Enhancing Autonomous Satellite Communication Systems with Weather-Aware Scheduling and Reconfiguration

NASA currently provides communication support to over 100 satellite missions, and the agency is driving developments in Ka-band communications and network management automation to support additional future missions. At Ka-band frequencies, rain can degrade a communication link by more than 10 dB, which may be mitigated by agile scheduling and data rate control. We present a weather forecasting module for Ka-band communications that is intended to be used in an autonomous network management service that employs machine-to-machine scheduling systems for dynamic user access opportunities. Our forecasting module (NIMBUS) runs on AWS Cloud, consumes the freely and publicly available NOAA MRMS precipitation rate dataset (1km x 1km x 2-min), produces 30-minute Nowcasts using the pySTEPS algorithm, and publishes high level ground station specific link quality predictions. We evaluate two potential NIMBUS outputs, a binary classifier that predicts rain attenuation greater than 3 dB and a rain attenuation estimator, and we backtest these outputs using one year of power measurement data collected from observations of the geostationary ANIK F2 satellite’s Ka-band beacon. We report, with a 30-minute lead time, a binary classifier accuracy of 84% and an estimator RMSE of 1.67 dB. Additionally, we discuss how the NIMBUS module could be incorporated into a user-initiated service framework to enable weather-aware scheduling and reconfiguration. Operating a static link budget with minimal link margin can increase network operation costs by creating additional scheduling tasks due to failed packets, which may require human intervention and/or lead to inefficient asset utilization. The proposed system aims to increase throughput by reducing link margin, while mitigating increases in network operations costs by leveraging autonomous machine-to-machine scheduling, shortened prediction lead times, and advances in precipitation Nowcasting.

satellite communications↗

NASA NTRS2009

NASA's Earth Observing Data and Information System

NASA's Earth Observing System Data and Information System (EOSDIS) has been a central component of NASA Earth observation program for over 10 years. It is one of the largest civilian science information system in the US, performing ingest, archive and distribution of over 3 terabytes of data per day much of which is from NASA s flagship missions Terra, Aqua and Aura. The system supports a variety of science disciplines including polar processes, land cover change, radiation budget, and most especially global climate change. The EOSDIS data centers, collocated with centers of science discipline expertise, archive and distribute standard data products produced by science investigator-led processing systems. Key to the success of EOSDIS is the concept of core versus community requirements. EOSDIS supports a core set of services to meet specific NASA needs and relies on community-developed services to meet specific user needs. EOSDIS offers a metadata registry, ECHO (Earth Observing System Clearinghouse), through which the scientific community can easily discover and exchange NASA s Earth science data and services. Users can search, manage, and access the contents of ECHO s registries (data and services) through user-developed and community-tailored interfaces or clients. The ECHO framework has become the primary access point for cross-Data Center search-and-order of EOSDIS and other Earth Science data holdings archived at the EOSDIS data centers. ECHO s Warehouse Inventory Search Tool (WIST) is the primary web-based client for discovering and ordering cross-discipline data from the EOSDIS data centers. The architecture of the EOSDIS provides a platform for the publication, discovery, understanding and access to NASA s Earth Observation resources and allows for easy integration of new datasets. The EOSDIS also has developed several methods for incorporating socioeconomic data into its data collection. Over the years, we have developed several methods for determining needs of the user community including use of the American Customer Satisfaction Index and a broad metrics program.

Mitchell, Andrew E.↗

NASA NTRS2007

Grid Task Execution

IPG Execution Service is a framework that reliably executes complex jobs on a computational grid, and is part of the IPG service architecture designed to support location-independent computing. The new grid service enables users to describe the platform on which they need a job to run, which allows the service to locate the desired platform, configure it for the required application, and execute the job. After a job is submitted, users can monitor it through periodic notifications, or through queries. Each job consists of a set of tasks that performs actions such as executing applications and managing data. Each task is executed based on a starting condition that is an expression of the states of other tasks. This formulation allows tasks to be executed in parallel, and also allows a user to specify tasks to execute when other tasks succeed, fail, or are canceled. The two core components of the Execution Service are the Task Database, which stores tasks that have been submitted for execution, and the Task Manager, which executes tasks in the proper order, based on the user-specified starting conditions, and avoids overloading local and remote resources while executing tasks.

Hu, Chaumin↗