المؤلفون: Leia Stirling, Damian Kelty-Stephen, Richard Fineman, Monica L. H. Jones, Byoung-Keon Daniel Park, Matthew P. Reed, Joseph Parham, Hyeg Joo Choi

المصدر: Human Factors: The Journal of the Human Factors and Ergonomics Society. 62(3):424-440

URL الوصول: https://ntrs.nasa.gov/citations/14020000722124

المؤلفون: Le, Charles, Chan, Samuel, Cheng, Frank, Fang, Winston, Fischman, Mark, Hensley, Scott, Johnson, Robert, Jourdan, Michael, Marina, Miguel, Parham, Bruce, Rogez, Francois, Rosen, Paul, Shah, Biren, Taft, Stephanie

مصطلحات موضوعية: Communications And Radar

الوصف: We present a real-time high-performance and fault-tolerant FPGA-based hardware architecture for the processing of synthetic aperture radar (SAR) images in future spaceborne system. In particular, we will discuss the integrated design approach, from top-level algorithm specifications and system requirements, design methodology, functional verification and performance validation, down to hardware design and implementation.

URL الوصول: https://ntrs.nasa.gov/citations/20060043109

المؤلفون: Gutierrez-Luaces, B. O, Marina, M, Parham, B

المصدر: The Telecommunications and Data Acquisition Report.

مصطلحات موضوعية: Electronics And Electrical Engineering

الوصف: Performance results of a digital test signal-generator hardware-demonstration unit are reported. Capabilities available include baseband and intermediate frequency (IF) spectrum generation, for which test results are provided. Repeatability in the setting of a given signal-to-noise ratio (SNR) when a baseband or an IF spectrum is being generated ranges from 0.01 dB at high SNR's or high data rates to 0.3 dB at low data rates or low SNR's. Baseband symbol SNR and carrier SNR (Pc/No) accuracies of 0.1 dB were verified with the built-in statistics circuitry. At low SNR's that accuracy remains to be fully verified. These results were confirmed with measurements from a demodulator synchronizer assembly for the baseband spectrum generation, and with a digital receiver (Pioneer 10 receiver) for the IF spectrum generation.

Relation: Piloting Vertical Flight Aircraft: A Conference on Flying Qualities and Human Factors

URL الوصول: https://ntrs.nasa.gov/citations/19940009909

المؤلفون: O'Brien, James J, Parham, Fred

المصدر: Monthly Weather Review. 120(8 Au)

مصطلحات موضوعية: Oceanography

الوصف: In the last several years many scientists have been using poorly resolved coupled models to study the ENSO. It has been very common to state that an ENSO cycle found in a model cannot have oceanic Kelvin waves as a mechanism because such waves do not exist in an ocean model with coarse grid spaing. In this note it is demonstrated that equatorial Kelvin waves can exist in models with coarse grids.

URL الوصول: https://ntrs.nasa.gov/citations/19920067017

المؤلفون: Choi, Gene, Jones, David L, Morris, James, Parham, Martin, Stephens, Jim, Yancey, Gregg

مصطلحات موضوعية: Spacecraft Design, Testing And Performance

الوصف: A mechanical design team was formed to design a foot for the lunar utility vehicle SKITTER. The primary design was constrained to be a ski pole design compatible with the existing femur-tibia design legs. The lunar environment had several important effects on the foot design. Three materials were investigated for the SKITTER foot: aluminum alloys, cold worked stainless steel alloys, and titanium alloys. Thin film coatings were investigated as a method of wear reduction for the foot. The performance of the foot is dependent on the action of the legs. The range of motion for the legs was determined to be vertical to 15 degrees above horizontal. An impact analysis was performed for the foot movement, but the results were determined to be inconclusive due to unknown soil parameters. The initial foot design configuration consisted of an annulus attached to the pointed pole. The annulus was designed to prevent excess sinkage. Later designs call for a conical shaped foot with a disk at the point of the tibia attachment. The conical design was analyzed for strength and deflection by two different approaches. A deformable body analysis was performed for the foot under crane load in crane position, and also under actuator load in the vertical position. In both cases, the deflection of the foot was insignificant and the stresses well below the strength of the titanium alloy.

URL الوصول: https://ntrs.nasa.gov/citations/19910002469

المؤلفون: Houser, B. C, Paine, G, Rubenstein, L. D, Parham, O. Bruce, Jr, Graves, W, Bradley, C

المصدر: NASA Tech Briefs. 10(1)

مصطلحات موضوعية: Electronic Systems

الوصف: Data compression allows video signals to be transmitted economically on telephone circuits. Telephone lines transmit television signals to remote traffic-control center. Lines also carry command signals from center to TV camera and compressor at highway site. Video system with television cameras positioned at critical points on highways allows traffic controllers to determine visually, almost immediately, exact cause of traffic-flow disruption; e.g., accidents, breakdowns, or spills, almost immediately. Controllers can then dispatch appropriate emergency services and alert motorists to minimize traffic backups.

URL الوصول: https://ntrs.nasa.gov/citations/19860000019

المؤلفون: Leritz, J, Rasser, T, Stone, E, Lockhart, B, Nobles, W, Parham, J, Eimers, D, Peterson, D, Barnhart, W, Schrock, S

مصطلحات موضوعية: Space Transportation

الوصف: The feasibility and economics of mounting and operating a set of solar scientific instruments in the backup Skylab Apollo Telescope Mount (ATM) hardware was evaluated. The instruments used as the study test payload and integrated into the ATM were: the Solar EUV Telescope/Spectrometer; the Solar Active Region Observing Telescope; and the Lyman Alpha White Light Coronagraph. The backup ATM hardware consists of a central cruciform structure, called the "SPAR', a "Sun End Canister' and a "Multiple Docking Adapter End Canister'. Basically, the ATM hardware and software provides a structural interface for the instruments; a closely controlled thermal environment; and a very accurate attitude and pointing control capability. The hardware is an identical set to the hardware that flow on Skylab.

URL الوصول: https://ntrs.nasa.gov/citations/19830004875