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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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Table yields best linear invariant /BLI/ estimates for log of reliable life under censored life tests, permitting reliability estimations in failure analysis of items with multiple flaws. These BLI estimates have uniformly smaller expected loss than Gauss-Markov best linear unbiased estimates.
Structure theorem for time invariant multivariable linear systems
Cyclic arithmetic codes and their distance properties with demonstration of modular arithmetic weight invariance to code word cyclic shifts
Gauge invariant theory of motion of singularities in linear approximation
Computational algorithm to mechanize theory of optimal time-invariant output-feedback controllers - Vol. 3
Stain rate sensitive constitutive equations using yield criterion which incorporates second and third invariants of stress deviator
Physical and geometrical properties of dust filled universes, using left invariant metrics compatible with Einstein equations
Electric propulsion spacecraft mission performance scaling laws for invariant trajectory, obtaining optimum gross payload over wide range of system input parameters
Turbulent shear flows transport properties, computing atmospheric and vortex motions by invariant modeling of Reynolds stress term in boundary layer momentum equation
Block decomposition of linear time invariant multivariable control systems
Electrostatic waves high order interaction in collisionless plasma, deriving coupling constants from energy conservation and invariance under time reversal
Optimal characteristics for single-input single- output memoryless time invariant nonlinear dynamic systems
Convergence of identification scheme for scalar- input-scalar-output linear systems with random inputs, applying invariant set theorem for random systems
Optimal fixed dimensionality dynamic compensator design for linear time-invariant closed-loop system based on quadratic cost and gain criteria
Visual evoked potential relationship to apparent size reduction of invariant retinal image
Parameter optimization of linear time invariant nutation damper by second Liapunov method
Unified electrical machine theory with allowance for space harmonics effects, transforming time- dependent linear differential equations into linear time-invariant equations
The application of linear stochastic optimal control theory to the design of the control system for the air intake (inlet) of a supersonic air-breathing propulsion system is discussed. The controls must maintain a stable inlet shock position in the presence of random airflow disturbances and prevent inlet unstart. Two different linear time invariant control systems are developed. One is designed to minimize a nonquadratic index, the expected frequency of inlet unstart, and the other is designed to minimize the mean square value of inlet shock motion. The quadratic equivalence principle is used to obtain the best linear controller that minimizes the nonquadratic performance index. The two systems are compared on the basis of unstart prevention, control effort requirements, and sensitivity to parameter variations.