14,501 research outputs found

    Hypersonic aerodynamic problems at re-entry of space vehicles

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    Hypersonic aerodynamic problems at space vehicle reentry - plasma effects on communications blackout, hypersonic flow, and atmospheric entr

    Geometric foundations of the theory of feedback equivalence

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    A description of feedback control is presented within the context of differential equations, differential geometry, and Lie theory. Work related to the integration of differential geometry with the control techniques of feedback linearization is summarized. Particular attention is given to the application of the theory of vector field systems. Feedback invariants for control systems in state space form are also addressed

    Control of echolocation pulses by neurons of the nucleus ambiguus in the rufous horseshoe bat, Rhinolophus rouxi

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    1. Horseradish peroxidase was applied by iontophoretic injections to physiologically identified regions of the laryngeal motor nucleus, the nucleus ambiguus in the CF/FM batRhinolophus rouxi. 2. The connections of the nucleus ambiguus were analysed with regards to their possible functional significance in the vocal control system, in the respiration control system, and in mediating information from the central auditory system. 3. The nucleus ambiguus is reciprocally interconnected with nuclei involved in the generation of the vocal motor pattern, i.e., the homonomous contralateral nucleus and the area of the lateral reticular formation. Similarly, reciprocal connections are found with the nuclei controlling the rhythm of respiration, i.e., medial parts of the medulla oblongata and the parabrachial nuclei. 4. Afferents to the nucleus ambiguus derive from nuclei of the descending vocalization system (periaqueductal gray and cuneiform nuclei) and from motor control centers (red nucleus and frontal cortex). 5. Afferents to the nucleus ambiguus, possibly mediating auditory influence to the motor control of vocalization, come from the superior colliculus and from the pontine nuclei. The efferents from the pontine nuclei are restricted to rostral parts of the nucleus ambiguus, which hosts the motoneurons of the cricothyroid muscle controlling the call frequency

    Hypersonic flow of air past a circular cylinder with non-equilibrium oxygen dissociation including dissociation of the free stream

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    Hypersonic inviscid flow past a circular cylinder with nonequilibrium oxygen dissociation and dissociation of the free strea

    Noise diffraction patterns eliminated in coherent optical systems

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    Lens rotation technique of noise diffraction pattern elimination spreads diffracted energy, normally concentrated over small area of image, over much larger annular area. Technique advantages include simplified lens selecting process, reduced clean room requirements, and low cost equipment requirements

    RSB Decoupling Property of MAP Estimators

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    The large-system decoupling property of a MAP estimator is studied when it estimates the i.i.d. vector x\boldsymbol{x} from the observation y=Ax+z\boldsymbol{y}=\mathbf{A}\boldsymbol{x}+\boldsymbol{z} with A\mathbf{A} being chosen from a wide range of matrix ensembles, and the noise vector z\boldsymbol{z} being i.i.d. and Gaussian. Using the replica method, we show that the marginal joint distribution of any two corresponding input and output symbols converges to a deterministic distribution which describes the input-output distribution of a single user system followed by a MAP estimator. Under the bbRSB assumption, the single user system is a scalar channel with additive noise where the noise term is given by the sum of an independent Gaussian random variable and bb correlated interference terms. As the bbRSB assumption reduces to RS, the interference terms vanish which results in the formerly studied RS decoupling principle.Comment: 5 pages, presented in Information Theory Workshop 201

    High performance structures

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    Materials selection, structural geometry, proof testing and statistical screening, prestressing, and system energy as tools for designing optimum trusses and other high performance structure

    Studies in prestressed and segmented brittle structures

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    Application of nonlinear bending theory to prestressed and segmented brittle structure
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