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At least 775 records · Page 43

Data Interfaces for Automated Vehicle Services - A Municipality Perspective

As Automated Vehicle (AV) services proliferate, data sharing between AV operators and municipal agents is assuming greater importance. Information on the dynamic nature of the road system such as incidents to avoid, weather hazards (such as flooding), construction and detours, as well as active safety concerns (e.g. - riots) is important for AV operators. Such information cannot be directly sensed from a vehicle's sensor array, but instead must be communicated in a timely and trustworthy channel. Municipalities are interested in pushing this information to AV operators to support emergency response efforts, reduce traffic in construction zones, and generally improve operation of the system. Similarly, information on vehicle safety such as disengagements, as well as critical information on the use of roadway system (trips, origin and destination patterns) are important performance factors for municipalities to understand utilization and plan for appropriate infrastructure. As mobility shifts to on-demand options, the need for safe and coordinated pick-up and drop-off zones will increase (potentially reducing parking needs). For all of these reasons, communication flows between AV operators and municipalities are becoming increasingly important. This paper investigates the functions, emerging practices and protocols for sharing of such critical data, and identifies gaps in and challenges in existing practices. Additionally, case studies are used to highlight the impacts of data sharing between AV operators and municipalities.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

Apollo spacecraft pyrotechnics

Apollo spacecraft pyrotechnics on lunar landing mission, considering standard initiator, modular cartridges, noninterchangeability of special purpose devices, postmanufacture indexing and data system

Simmons, W. H.↗

Application of selection techniques to electric-propulsion options on an advanced synchronous satellite

This paper addresses the comparison of several candidate auxiliary-propulsion systems and system combinations for an advanced synchronous satellite. Economic selection techniques, evolved at the Jet Propulsion Laboratory, are used as a basis for system option comparisons. Electric auxiliary-propulsion types considered include pulsed plasma and ion bombardment, with hydrazine systems used as a state-of-the-art reference. Current as well as projected electric-propulsion system performance data are used, as well as projected hydrazine system costs resulting from NASA standardization program projections.

Holcomb, L. B.↗

Effects of outdoor exposure on solar cell modules in the ERDA/NASA Lewis Research Center Systems Test Facility

The effects of outdoor exposure were determined by comparing standard I-V data obtained for the as-received modules with similar data obtained after removal from the field and cleaning with detergent solution. All modules measured in this way exhibited nonrecoverable degradation in P sub maximum varying from 4 to 7 percent. One module exposed for 41 days exhibited partial cell discoloration, loss of front surface metallization over the discolored portion, and a decrease in P sub maximum of 7 percent, tentatively attributed to cell damage. Measurements before and after cleaning showed a recoverable degradation due to dirt accumulation. This recoverable loss in power was 11 percent after 245 days in the field for one brand of module, 6 percent after 48 days for another brand, and 4 1/2 percent for the third brand.

Weinberg, I.↗

Characteristics of 30-centimeter mercury ion thrusters

The technology development of the 30 centimeter J series mercury ion thruster for prime propulsion application in solar electric propulsion systems is described. Thruster design is reviewed. A standardized set of test and data recording procedures formulated to allow for the characterization of the J series thruster is described. Characteristics measured are the magnetic baffle characterization, the neutralizer characterization, perveance, the minimum eV/ion measurement, and the electrical and propellant utilization efficiency measurements. Test results are presented.

Maloy, J. E.↗

Use of the VAS water vapor imagery to analyze upper-level flow patterns

Infrared (IR) channels which are available and are developed for operational use were examined. The Visible Infrared Spin-Scan Radiometer (VISSR) Atmospheric Sounder (VAS) was launched. This instrument has a radiometer consisting of the standard visible channel detectors and six thermal detectors that detect IR radiation in 12 spectral bands. Any one of the 11 new IR channels can be substituted for the standard 11.5 micro m window channel when the satellite is operating in the standard VISSP mode and provides data in image form through the GOES distribution system.

Anderson, R. K.↗

Maximum Normalized Rate as a Flying Qualities Parameter

Discrete attitude commands have become a standard task for flying qualities evaluation and control system testing. Much pilot opinion data is now available for ground-based and in-flight simulations, but adequate performance measures and prediction methods have not been established. The Step Target Tracking Prediction method, introduced in 1978, correlated time-on-target and rms tracking data with NT-33 in-flight longitudinal simulations, but did not employ parameters easily measured in manned flight and simulation. Recent application of the Step Target Tracking Prediction method to lateral flying qualities analysis has led to a new measure of performance. This quantity, called Maximum Normalized Rate (MNR), reflects the greatest attitude rate a pilot can employ during a discrete maneuver without excessive overshoot and oscillation. MNR correlates NT-33 lateral pilot opinion ratings well, and is easily measured during flight test or simulation. Futhermore, the Step Target MNR method can be used to analyze large amplitude problems concerning rate limiting and nonlinear aerodynamics.

Onstott, E. D.↗

Advanced satellite system architecture for VSATs with ISDN compatibility

This paper describes a future communications satellite system architecture concept which allows the use of Very Small Aperature Terminals (VSATs) of 1.2 m to 1.8 m diameter and which provides access according to the international Integrated Services Digital Network (ISDN) standard. This satellite system design could make dial-up integrated voice and data service available nationwide and perhaps worldwide. The paper gives a conceptual system design based on the year 1995 technology for the communications satellite, the earth terminal, and the ground-based master control station and interface to the terrestrial ISDN network.

Jorasch, Ronald E.↗

A hydrogen maser with cavity auto-tuner for timekeeping

A hydrogen maser frequency standard for timekeeping was worked on at the Shanghai Observatory. The maser employs a fast cavity auto-tuner, which can detect and compensate the frequency drift of the high-Q resonant cavity with a short time constant by means of a signal injection method, so that the long term frequency stability of the maser standard is greatly improved. The cavity auto-tuning system and some maser data obtained from the atomic time comparison.

C. F. Lin↗

Earth rotation parameters from an on-site study of laser ranging data

A multi-faceted effort was maintained to achieve the following goals: (1) provide for state-of-the-art, on-site, near-real-time Earth orientation parameter determinations at levels of precision and accuracy commensurate with a 'quick-look' type of an analysis, using the lunar laser ranging (LLR) data type from the McDonald Laser Ranging Station (MLRS) and other LLR facilities around the world; (2) create a state-of-the-art, highly transportable, LLR-based Earth orientation solution package, which could be easily implemented at LLR facilities other than the MLRS; (3) accommodate, within the routine MLRS lunar range prediction and Earth orientation data analysis software packages, the standard set of Jet Propulsion Laboratory (JPL) Solar System ephemerides, lunar librations, and Solar System partial derivatives; and (4) examine, wherever possible, opportunities for the performance of state-of-the-art, on-site, joint, simultaneous, quick-look analysis for Earth orientation parameters, using both MLRS lunar and LAGEOS (and, perhaps, Etalon) ranging observations, as well as from multiple LLR station observations. Excellent results were obtained at all levels of effort and it can be said that all of these goals were attained. The reader is referred to the complete series of our semi-annual reports for a full description of our efforts.

Shelus, Peter J.↗

An MPA-IO interface to HPSS

This paper describes an implementation of the proposed MPI-IO (Message Passing Interface - Input/Output) standard for parallel I/O. Our system uses third-party transfer to move data over an external network between the processors where it is used and the I/O devices where it resides. Data travels directly from source to destination, without the need for shuffling it among processors or funneling it through a central node. Our distributed server model lets multiple compute nodes share the burden of coordinating data transfers. The system is built on the High Performance Storage System (HPSS), and a prototype version runs on a Meiko CS-2 parallel computer.

Jones, Terry↗

Integration of the White Sands Complex into a Wide Area Network

The NASA White Sands Complex (WSC) satellite communications facility consists of two main ground stations, an auxiliary ground station, a technical support facility, and a power plant building located on White Sands Missile Range. When constructed, terrestrial communication access to these facilities was limited to copper telephone circuits. There was no local or wide area communications network capability. This project incorporated a baseband local area network (LAN) topology at WSC and connected it to NASA's wide area network using the Program Support Communications Network-Internet (PSCN-I). A campus-style LAN is configured in conformance with the International Standards Organization (ISO) Open Systems Interconnect (ISO) model. Ethernet provides the physical and data link layers. Transmission Control Protocol and Internet Protocol (TCP/IP) are used for the network and transport layers. The session, presentation, and application layers employ commercial software packages. Copper-based Ethernet collision domains are constructed in each of the primary facilities and these are interconnected by routers over optical fiber links. The network and each of its collision domains are shown to meet IEEE technical configuration guidelines. The optical fiber links are analyzed for the optical power budget and bandwidth allocation and are found to provide sufficient margin for this application. Personal computers and work stations attached to the LAN communicate with and apply a wide variety of local and remote administrative software tools. The Internet connection provides wide area network (WAN) electronic access to other NASA centers and the world wide web (WWW). The WSC network reduces and simplifies the administrative workload while providing enhanced and advanced inter-communications capabilities among White Sands Complex departments and with other NASA centers.

Boucher, Phillip Larry↗

An MPI-IO Interface to HPSS

This paper describes an implementation of the proposed MPI-IO standard for parallel I/O. Our system uses third-party transfer to move data over an external network between the processors where it is used and the I/O devices where it resides. Data travels directly from source to destination, without the need for shuffling it among processors or funneling it through a central node. Our distributed server model lets multiple compute nodes share the burden of coordinating data transfers. The system is built on the High Performance Storage System (HPSS), and a prototype version runs on a Meiko CS-2 parallel computer.

Parallel Processing↗

Maximum Normalized Rate as a Flying Qualities Parameter

Discrete attitude commands have become a standard task for flying qualities evaluation and control system testing. Much pilot opinion data is now available for ground-based and in-flight simulations, but adequate performance measures and prediction methods have not been established. The Step Target Tracking Prediction method, introduced in 1978, correlated time-on-target and rms tracking data with NT-33 in-flight longitudinal simulations, but did not employ parameters easily measured in manned flight and simulation. Recent application of the Step Target Tracking Prediction method to lateral flying qualities analysis has led to a new measure of performance. This quantity, called Maximum Normalized Rate (MNR), reflects the greatest attitude rate a pilot can employ during a discrete maneuver without excessive overshoot and oscillation. MNR correlates NT-33 lateral pilot opinion ratings well, and is easily measured during night test or simulation. Furthermore, the Step Target MNR method can be used to analyze large amplitude problems concerning rate limiting and nonlinear aerodynamics.

Onstott, E. D.↗

One Millimeter Horizontal Precision Over a 41 Km Baseline Using P-Codeless Data

High accuracy geodetic solutions at the few ppb level have become fairly standard with data from a global network of P-code Global Positioning System (GPS) receivers. Used as a measurement tool, it has numerous scientific applications including the monitoring of crustal motion, volcanic and post-seismic uplift, co- and post-seismic displacements in fault zones and media delay calibration and monitoring.

Global Positioning System↗

Cryogenic monocrystalline silicon Fabry-Perot cavity for the stabilization of laser frequency

A 1.6 kg silicon monocrystal was used to make a Fabry-Perot optical cavity operated at cryogenic temperatures. High-resolution thermal expansion measurements were made as the silicon cooled to 4.2 K, in order to characterize the cavity as a length reference standard. A helium-neon laser was then locked to a transmission resonance at liquid-helium temperatures, and the laser frequency tracked the cavity resonance with error fluctuations at the level of 10 Hz/sq rt Hz in the bandwidth dc to 1 Hz. Implications of the combined set of data, thermal expansion plus frequency-tracking fluctuations, for using such a system as a frequency standard are discussed.

Richard, J.-P.↗

AI-Ready Control System for the Fermilab Accelerator Complex

Reliable, high-intensity operation of the Fermilab Accelerator Complex is critical to the success of the Long-Baseline Neutrino Facility and Deep Underground Neutrino Experiment. We describe the requirements and infrastructure necessary to support routine use of artificial intelligence and machine learning (AI/ML) in the accelerator control system. Three capabilities are identified: a machine learning operations (MLOps) framework standardizing the lifecycle of AI/ML automation from data management through deployment and monitoring; a data quality framework defining and enforcing standards required to build trustworthy AI/ML applications; and workflow integration with large language models to assist physicists, engineers, and operators with information retrieval, code development, and routine analysis. Use cases spanning beam diagnostics, beam control, and support system automation illustrate the technical requirements across the complex.

43 PARTICLE ACCELERATORS↗

Software For Clear-Air Doppler-Radar Display

System of software developed to present plan-position-indicator scans of clear-air Doppler radar station on color graphical cathode-ray-tube display. Designed to incorporate latest accepted standards for equipment, computer programs, and meteorological data bases. Includes use of Ada programming language, of "Graphical-Kernel-System-like" graphics interface, and of Common Doppler Radar Exchange Format. Features include portability and maintainability. Use of Ada software packages produced number of software modules reused on other related projects.

Johnston, Bruce W.↗