SEARCH · Engineering Papers
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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Detailed analysis of radiation data from Gemini 4 and 7 proton-electron spectrometer experiments
Ground support, noise level measurements, data analyses, and equipment developed for sound ranging arrays in rocket grenade experiment
A burner is designed to model on a large scale (millimeters) the complex vapor phase processes that take place on awkwardly small scales (about a hundred microns) in the combustion of practical AP/ composite propellants at conventional pressures. Binder vapor evolution is modeled with gaseous fuel (ethane in the experiments reported) flow through a porous plate and oxidizer vapor with the flow of a gaseous oxidizer (air and enriched air in the experiments reported) through discrete holes in the porous plate. Measured flame standoff distance and surface temperature variations are consistent with theoretical predictions at atmospheric pressure. Data obtained at several atmospheres are discussed in the light of the current theories of propellant burning that place varying emphasis on the roles of chemical kinetics and fluid dynamic diffusion/mixing in the vapor phase of a burning composite propellant. The potential and proposed future applications of the burner are indicated.
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Clarissa, an experimental voice enabled procedure browser that has recently been deployed on the International Space Station, is as far as we know the first spoken dialog system in space. We describe the objectives of the Clarissa project and the system's architecture. In particular, we focus on three key problems: grammar-based speech recognition using the Regulus toolkit; methods for open mic speech recognition; and robust side-effect free dialogue management for handling undos, corrections and confirmations. We first describe the grammar-based recogniser we have build using Regulus, and report experiments where we compare it against a class N-gram recogniser trained off the same 3297 utterance dataset. We obtained a 15% relative improvement in WER and a 37% improvement in semantic error rate. The grammar-based recogniser moreover outperforms the class N-gram version for utterances of all lengths from 1 to 9 words inclusive. The central problem in building an open-mic speech recognition system is being able to distinguish between commands directed at the system, and other material (cross-talk), which should be rejected. Most spoken dialogue systems make the accept/reject decision by applying a threshold to the recognition confidence score. NASA shows how a simple and general method, based on standard approaches to document classification using Support Vector Machines, can give substantially better performance, and report experiments showing a relative reduction in the task-level error rate by about 25% compared to the baseline confidence threshold method. Finally, we describe a general side-effect free dialogue management architecture that we have implemented in Clarissa, which extends the "update semantics'' framework by including task as well as dialogue information in the information state. We show that this enables elegant treatments of several dialogue management problems, including corrections, confirmations, querying of the environment, and regression testing.
Evaluation of radio beacon data from satellite observation of earth exosphere - data scaling techniques
Direct current, ionospheric rocket sounding probe - theoretical determinations of ion temperature and density, electron temperature, and vehicle potential
Spacecraft structures and systems materials handbook
Statistical decision theory applied to problems associated with Martian biological exploration program
Effect of atmospheric humidity, pressure, and temperature on electromagnetic wave propagation
Weak shock effects and chemistry of lower D region, and blunt supersonic probe theory and first order corrections
Task identification, requirements, and justification for use in manned flight research program - size influence of lifting body entry vehicle on costs and potentials
Automatic picture transmission stations evaluation of meteorological charts and cloud cover photographs relayed from ATS
Light beam triangulation technique for atmospheric measurements
Comparison of theoretical Apollo water impact data with scale model experimental results
Technology utilization by small industrial plants
Interplanetary field and particle instrument measurements of Mariner 4 mission