Search NASA⌕ Search

SEARCH · Search NASA

Results for “integral operator”

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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Estimation of local planetary gravity fields using line of sight gravity data and an integral operator

A novel method is presented for mapping line-of-sight gravity data (LOSGD) joining planetary probes and observers during Doppler tracking operations, with a view to geodetic and geophysical applications. LOSGD are in this case mapped as gravity anomalies along a radial direction, at constant altitude, using an inversion procedure in conjunction with a Tikhonov-Arsenine regularization method. The application of different regularization-parameter choices to a synthetic case is followed by application to the real case of Pioneer-Venus orbiter data for Venus' Gula Mons.

Barriot, J. P.↗
NASA NTRS2009

Wide-temperature integrated operational amplifier

The present invention relates to a reference current circuit. The reference circuit comprises a low-level current bias circuit, a voltage proportional-to-absolute temperature generator for creating a proportional-to-absolute temperature voltage (VPTAT), and a MOSFET-based constant-IC regulator circuit. The MOSFET-based constant-IC regulator circuit includes a constant-IC input and constant-IC output. The constant-IC input is electrically connected with the VPTAT generator such that the voltage proportional-to-absolute temperature is the input into the constant-IC regulator circuit. Thus the constant-IC output maintains the constant-IC ratio across any temperature range.

Mojarradi, Mohammad↗
NASA NTRS2015

Strategic Time-Based Metering that Assures Separation for Integrated Operations in a Terminal Airspace

This paper reports an algorithm for strategic time-based metering of air traffic arriving and departing from a large ( tens of nautical miles) area (called here, the commitment region) around an airport or metroplex. The algorithm assures separation continuously in time and avoids a dictation of intent to an aircraft crew. This is accomplished by allowing an aircraft (specifically, its Flight Management System) to specify, and commit to, an intended route and ground speed profile along that route within the commitment region, and by supplying the time at which to enter the region to the aircraft crew. The airspace that comprises the commitment region need not be confined to the terminal airspace and can include some of the enroute space: the size and shape of the commitment region are parameters in the algorithm. An exact formula for including speed profile uncertainty in the algorithm is provided. The algorithm is applied to a number of data sets recorded during actual air traffic operations in the Southern California TRACON in July of 2014 and the Atlanta TRACON in November and December of 2013. The results of the numerical simulations indicate that the algorithm succeeds at keeping the aircraft separated, but introduces, in its current implementation, more separation than that observed in actual operations. This excess separation can be reduced by modeling more accurately the Visual Flight Rules separation practices, a direction for future research.

air traffic management↗
NASA NTRS1996

Integrating International Space Station payload operations

The payload operations support for the International Space Station (ISS) payload is reported on, describing payload activity planning, payload operations control, payload data management and overall operations integration. The operations concept employed is based on the distribution of the payload operations responsibility between the researchers and ISS partners. The long duration nature of the ISS mission dictates the geographical distribution of the payload operations activities between the different national centers. The coordination and integration of these operations will be assured by NASA's Payload Operations Integration Center (POIC). The prime objective of the POIC is the achievement of unified operations through communication and collaboration.

Noneman, Steven R.↗
NASA NTRS1988

Alpha: A real-time decentralized operating system for mission-oriented system integration and operation

Alpha is a new kind of operating system that is unique in two highly significant ways. First, it is decentralized transparently providing reliable resource management across physically dispersed nodes, so that distributed applications programming can be done largely as though it were centralized. And second, it provides comprehensive, high technology support for real-time system integration and operation, an application area which consists predominately of aperiodic activities having critical time constraints such as deadlines. Alpha is extremely adaptable so that it can be easily optimized for a wide range of problem-specific functionality, performance, and cost. Alpha is the first systems effort of the Archons Project, and the prototype was created at Carnegie-Mellon University directly on modified Sun multiprocessor workstation hardware. It has been demonstrated with a real-time C(sup 2) application. Continuing research is leading to a series of enhanced follow-ons to Alpha; these are portable but initially hosted on Concurrent's MASSCOMP line of multiprocessor products.

Jensen, E. Douglas↗