Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “ADS”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Development of an intelligent interface for adding spatial objects to a knowledge-based geographic information system

Earth Scientists lack adequate tools for quantifying complex relationships between existing data layers and studying and modeling the dynamic interactions of these data layers. There is a need for an earth systems tool to manipulate multi-layered, heterogeneous data sets that are spatially indexed, such as sensor imagery and maps, easily and intelligently in a single system. The system can access and manipulate data from multiple sensor sources, maps, and from a learned object hierarchy using an advanced knowledge-based geographical information system. A prototype Knowledge-Based Geographic Information System (KBGIS) was recently constructed. Many of the system internals are well developed, but the system lacks an adequate user interface. A methodology is described for developing an intelligent user interface and extending KBGIS to interconnect with existing NASA systems, such as imagery from the Land Analysis System (LAS), atmospheric data in Common Data Format (CDF), and visualization of complex data with the National Space Science Data Center Graphics System. This would allow NASA to quickly explore the utility of such a system, given the ability to transfer data in and out of KBGIS easily. The use and maintenance of the object hierarchies as polymorphic data types brings, to data management, a while new set of problems and issues, few of which have been explored above the prototype level.

Campbell, William J.↗
NASA NTRS1989

Adding intelligence to scientific data management

NASA plans to solve some of the problems of handling large-scale scientific data bases by turning to artificial intelligence (AI) are discussed. The growth of the information glut and the ways that AI can help alleviate the resulting problems are reviewed. The employment of the Intelligent User Interface prototype, where the user will generate his own natural language query with the assistance of the system, is examined. Spatial data management, scientific data visualization, and data fusion are discussed.

Campbell, William J.↗
NASA NTRS1990

DSS 15, 45, and 65 34-meter high efficiency antenna radio frequency performance enhancement by tilt added to the subreflector during elevation angle changes

The focusing adjustments of the subreflectors of an az-el Cassegrainian antenna that uses only linear motions have always ended in lateral offsets of the phase centers at the subreflector's focus points at focused positions, which have resulted in small gain losses. How lateral offsets at the two focus points were eliminated by tilting the subreflector, resulting in higher radio frequency (RF) efficiencies at all elevation angles rotated from the rigging angles are described.

Katow, M. S.↗
NASA NTRS1990

A Solar Constant Model for Sun-climate Studies: 1600-2000AD

Discussed here is the solar constant model published recently (Schatten, 1988), but with a modified phasing and amplitude. This model enables the known solar constant variations to be calculated from known active region and quiet region solar parameters. The features which can be modelled are sunspots and faculae, the only two features which mark the photospheric continuum with their unusual contrast behavior. They include both the active region features (sunspots and faculae) and the quiet region features (global faculae). Although the direct influences of sunspots upon the solar constant leads to short term decreases, an opposite, nearly in phase, 11 year variation in the solar constant is modelled, thereby agreeing with the Active Cavity Radiometer Irradiance Monitor (ACRIM) and Earth Radiation Budget (ERB) secular trends observed. This opposite behavior results primarily from global faculae (polar, network, and active region). The main contributors to the global behavior are the network faculae. The model attributes the observed variations in the solar constant entirely to magnetic features in the solar atmosphere. The present model serves purely to model the secular (long term) trend in the solar constant. The model suggests a change of approx. 0.5 W/sq m for the differences between the late twentieth century solar constant and the 17th century solar constant. This supports Eddy's view that this difference could give rise to the glacial increase during the little ice age of the 17th century. Important for present day climate studies, is that it shows the recent peak activity (peaking in 1958) is associated with an atypically high value of the solar constant, with respect to the past few hundred years.

Schatten, Kenneth H.↗
NASA NTRS1991

Adding run history to CLIPS

To debug a C Language Integrated Production System (CLIPS) program, certain 'historical' information about a run is needed. It would be convenient for system builders to have the capability to request such information. We will discuss how historical Rete networks can be used for answering questions that help a system builder detect the cause of an error in a CLIPS program. Moreover, the cost of maintaining a historical Rete network is compared with that for a classical Rete network. We will demonstrate that the cost for assertions is only slightly higher for a historical Rete network. The cost for handling retraction could be significantly higher; however, we will show that by using special data structures that rely on hashing, it is also possible to implement retractions efficiently.

Tuttle, Sharon M.↗
NASA NTRS1993

Some lessons learned in three years with ADS-33C

Three years of using the U.S. Army's rotorcraft handling qualities specification, Aeronautical Design Standard - 33, has shown it to be surprisingly robust. It appears to provide an excellent basis for design and for assessment, however, as the subtleties become more well understood, several areas needing refinement became apparent. Three responses to these needs have been documented in this paper: (1) The yaw-axis attitude quickness for hover target acquisition and tracking can be relaxed slightly. (2) Understanding and application of criteria for degraded visual environments needed elaboration. This and some guidelines for testing to obtain visual cue ratings have been documented. (3) The flight test maneuvers were an innovation that turned out to be very valuable. Their extensive use has made it necessary to tighten definitions and testing guidance. This was accomplished for a good visual environment and is underway for degraded visual environments.

Key, David L.↗
NASA NTRS1993

Value added data archiving

Researchers in the Molecular Sciences Research Center (MSRC) of Pacific Northwest Laboratory (PNL) currently generate massive amounts of scientific data. The amount of data that will need to be managed by the turn of the century is expected to increase significantly. Automated tools that support the management, maintenance, and sharing of this data are minimal. Researchers typically manage their own data by physically moving datasets to and from long term storage devices and recording a dataset's historical information in a laboratory notebook. Even though it is not the most efficient use of resources, researchers have tolerated the process. The solution to this problem will evolve over the next three years in three phases. PNL plans to add sophistication to existing multilevel file system (MLFS) software by integrating it with an object database management system (ODBMS). The first phase in the evolution is currently underway. A prototype system of limited scale is being used to gather information that will feed into the next two phases. This paper describes the prototype system, identifies the successes and problems/complications experienced to date, and outlines PNL's long term goals and objectives in providing a permanent solution.

Berard, Peter R.↗
NASA NTRS1994

Adding tools to the open source toolbox: The Internet

The Internet offers researchers additional sources of information not easily available from traditional sources such as print volumes or commercial data bases. Internet tools such as e-mail and file transfer protocol (ftp) speed up the way researchers communicate and transmit data. Mosaic, one of the newest additions to the Internet toolbox, allows users to combine tools such as ftp, gopher, wide area information server, and the world wide web with multimedia capabilities. Mosaic has quickly become a popular means of making information available on the Internet because it is versatile and easily customizable.

Porth, Tricia↗
NASA NTRS1994

Adding intelligent services to an object oriented system

As today's software becomes increasingly complex, the need grows for intelligence of one sort or another to becomes part of the application, often an intelligence that does not readily fit the paradigm of one's software development. There are many methods of developing software, but at this time, the most promising is the object oriented (OO) method. This method involves an analysis to abstract the problem into separate 'objects' that are unique in the data that describe them and the behavior that they exhibit, and eventually to convert this analysis into computer code using a programming language that was designed (or retrofitted) for OO implementation. This paper discusses the creation of three different applications that are analyzed, designed, and programmed using the Shlaer/Mellor method of OO development and C++ as the programming language. All three, however, require the use of an expert system to provide an intelligence that C++ (or any other 'traditional' language) is not directly suited to supply. The flexibility of CLIPS permitted us to make modifications to it that allow seamless integration with any of our applications that require an expert system. We illustrate this integration with the following applications: (1) an after action review (AAR) station that assists a reviewer in watching a simulated tank battle and developing an AAR to critique the performance of the participants in the battle; (2) an embedded training system and over-the-shoulder coach for howitzer crewmen; and (3) a system to identify various chemical compounds from their infrared absorption spectra.

Robideaux, Bret R.↗