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Results for “Fidelity”
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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The Dynamic Assimilation Technique measures photosynthetic CO2 response curves with similar fidelity as steady-state approaches in half the time
The net CO2 assimilation (A) response to intercellular CO2 concentration (Ci) is a fundamental measurement in photosynthesis and plant physiology research. The conventional A/Ci protocols rely on steady-state measurements and take 15-40 minute per measurement, limiting data resolution or biological replication. Additionally, there are several CO2 protocols employed across the literature, without clear consensus as to the optimal protocol or systematic biases in their estimations. We compared the non-steady state Dynamic Assimilation Technique (DAT) protocol and the three most used CO2 protocols in steady-state measurements, and tested whether different CO2 protocols lead to systematic differences in estimations of the biochemical limitations to photosynthesis.
Modeling Dense Particle Flow in Multistage and Obstructed Flow Receivers Using High Fidelity Simulations
Particles are a leading contender for next-generation, concentrating solar power technologies, and the design of the particle receiver is critical to minimize the levelized cost of electricity. Falling particle receivers (FPRs) are a viable receiver concept, but many new designs feature complex particle obstructions that include dense discrete phase flows. This creates additional challenges for modeling as particle-to-particle interactions (i.e., collisions) and particle drag become more complex. To improve upon existing modeling strategies, a CFD-DEM simulation capability was created by coupling two independent codes: Sierra/Fuego and LAMMPS. A suitable receiver model was then defined using a traditional continuum-based model for the air and a granular model for the particle curtain. A sensitivity study was executed using this model to determine the relevance of different granular model inputs on important quantities of interest in obstructed flow FPRs: the particle velocity and curtain opacity. The study showed that the granular model inputs had little effect on the particle velocity magnitude and curtain opacity after an obstruction.
High-fidelity aerostructural optimization of tow-steered composite wings
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Assessing the fidelity of shallow-water carbonates as records of the Ni isotope composition of surface seawater
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Fidelity of the PCM telemetry data information for OGO-B-D-E-F, RAE-A, ISIS-A and OSO-D-E-F satellites
Performance accuracy of pulse code modulation telemetry data information system for scientific satellites
Geometric fidelity of three space television systems
Distortion characteristics of ESSA 7, Mariner 4, and Surveyor 7 TV systems for photogrammetric mapping
High-fidelity solar simulation for an ultrahigh vacuum facility
Solar simulator built into multiwall ultrahigh vacuum chamber, describing simulator and chamber modifications
Geometric fidelity of three space television systems
Geometric distortions in ESSA 7, Surveyor 7 and Mariner 4 TV systems caused by scale distortion, discussing stability of systematic component in magnitude and shape
Fidelity of space TV
Essa 7, Surveyor 7 and Mariner 4 space TV systems geometric distortions analysis and potentials in analytic photogrammetry and topographical mapping
A 2-cycle algorithm for source coding with a fidelity criterion.
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The effects of a visual fidelity criterion on the encoding of images
Shannon's rate-distortion function provides a potentially useful lower bound against which to compare the rate-versus-distortion performance of practical encoding-transmission systems. However, this bound is not applicable unless one can arrive at a numerically-valued measure of distortion which is in reasonable correspondence with the subjective evaluation of the observer or interpreter. We have attempted to investigate this choice of distortion measure for monochrome still images. This investigation has considered a class of distortion measures for which it is possible to simulate the optimum (in a rate-distortion sense) encoding. Such simulation was performed at a fixed rate for various measures in the class and the results compared subjectively by observers. For several choices of transmission rate and original images, one distortion measure was fairly consistently rated as yielding the most satisfactory appearing encoded images.
Results of an investigation to verify shuttle orbiter vehicle 102 aero characteristics utilizing an .05 scale hi-fidelity remote control model (39-0) in the Ames Research Center unitary wind tunnel, volume 5
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Results of an investigation to verify shuttle orbiter vehicle 102 aero characteristics utilizing and .05-scale hi-fidelity remote control model (39-0) in the Ames Research Center unitary wind tunnel (OA145C), volume 3
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Simulation fidelity and numerosity effects in CDTI experimentation
Twenty pilot workload assessment techniques were compared using a simulated flying task in which three levels of psychomotor workload were imposed. The experiment was conducted in a three degree of freedom motion base simulator. Opinion measures, spare mental capacity measures, physiological measures, eye movement behavior and primary task performance measures were evaluated. The primary task was an instrument landing system (ILS) approach and landing. All measures were recorded between the outer and middle markers on the approach. Three levels of psychomotor load were obtained by the combined manipulation of wind gust disturbance level and simulated aircraft pitch stability. Six instrument rated general aviation pilots participated in the experiment. Cooper-Harper ratings, WCI/TE ratings, time estimation standard deviation, pulse rate mean, and control movements per unit time demonstrated sensitivity to psychomotor load. No intrusion into primary task performance was found that the sensitivities of workload estimation techniques vary widely, and that only a few techniques appear to be sensitive to psychomotor load.
The window of visibility: A psychological theory of fidelity in time-sampled visual motion displays
Many visual displays, such as movies and television, rely upon sampling in the time domain. The spatiotemporal frequency spectra for some simple moving images are derived and illustrations of how these spectra are altered by sampling in the time domain are provided. A simple model of the human perceiver which predicts the critical sample rate required to render sampled and continuous moving images indistinguishable is constructed. The rate is shown to depend upon the spatial and temporal acuity of the observer, and upon the velocity and spatial frequency content of the image. Several predictions of this model are tested and confirmed. The model is offered as an explanation of many of the phenomena known as apparent motion. Finally, the implications of the model for computer-generated imagery are discussed.
Nimbus-earth radiation budget sensor characterization for improved data reduction fidelity
Detailed characterizations of flight spare earth flux sensors from the Nimbus Earth Radiation Budget (ERB) program have been performed which, when coupled with a more careful accounting of the orbital instrument environment, provide the potential for improved accuracy in the final data products. The characterizations included detailed field-of-view mappings, responses to transient long and short wavelength radiation, and response to sensor temperature changes. These sensor and environment characterizations, along with the outstanding low noise and stability properties of the ERB instrument signal processing system, promise improvement of the data accuracy to levels sufficient for long-term budget and climatological purposes. The combined data sets from Nimbus 6 and 7 are expected to span a period in excess of 10 years. The improvements in data accuracy are particularly significant over zonal latitude bands because the corrections are strongly latitude dependent.
Fidelity of Satellite Soundings
Two pattern recognition procedures to provide improvements to first guess fields for satellite temperature retrievals were developed. The first technique where a radiometer measurement is used to select one or more historical radiosonde temperature profiles as analog estimates of ambient thermal structure. Radiosondes are the vertical scales of the analogs. The vertical resolving power of the satellite radiometer is relevant only to a decision process. The analog selection process is much more effective if implemented in an orthogonalized space of measurement information. The second procedure partitions a priori dependent data into shape coherent pattern libraries using structure information inherent in the data itself. It is shown that the pattern recognition techniques are able to reduce first guess profile errors by nearly 50%. The impact of pattern recognition on temperature retrieval error is assessed by regression and physical iterative retrieval algorithms. The influence of improved first guess fields is markedly different on these two types of algorithm. Pattern recognition was a strong positive impact on the physical iterative method.